The Wairau Affray (called the Wairau Massacre in many older texts), on 17 June 1843, was the first serious clash of arms between Māori and the British settlers in New Zealand after the signing of the Treaty of Waitangi and the only one to take place on the South Island. The incident was sparked when a magistrate and a representative of the New Zealand Company, who held a fraudulent deed to land in the Wairau Valley in the north of the South Island, led a group of European settlers to attempt to clear Māori off the land and arrest Ngāti Toa chiefs Te Rauparaha and Te Rangihaeata. After the latter's wife was shot, fighting broke out. The Maori killed a total of 22 British settlers, several after their surrender, and four to six Māori were killed.
The incident heightened fears among settlers of an armed Māori insurrection. It created the first major challenge for Governor Robert FitzRoy, who took up his posting in New Zealand six months later. FitzRoy investigated the incident and exonerated Te Rauparaha and Te Rangihaeata, for which he was strongly criticised by settlers and the New Zealand Company. In 1944 a land claims commission investigation determined that the Wairau Valley had not been legally sold. The government was to pay compensation to the Rangitane iwi, determined to be the original owners.
The New Zealand Company had built a settlement around Nelson in the north of the South Island in 1840. It had planned to occupy 200,000 acres (810 km2), but by the end of the year, even as allotments were being sold in England, the company's agents in New Zealand were having difficulty in identifying available land, let alone buying it from local Māori, to form the settlement. The settlers began to purchase large areas of land directly from Māori, without consulting the newly established colonial government and often without establishing vendors' rights to sell the land. The situation led to tension and caused disputes between the two parties.
In January 1843 Captain Arthur Wakefield had been dispatched by the New Zealand Company to lead the first group of settlers to Nelson. He was the younger brother of Colonel Edward Gibbon Wakefield, one of the principal officers of the company, and William Wakefield. Arthur wrote to Edward that he had located the required amount of land at Wairau, an average distance of 25 km from Nelson. He said he held a deed to the land, having bought it from the widow of a whaling Captain John Blenkinsopp, who had bought it from Te Rauparaha of the Ngāti Toa iwi at Tuamarina. Wakefield wrote to the company in March 1843: "I rather anticipate some difficulty with the natives." 
The source of the likely difficulty was simple: the chiefs Te Rauparaha and Te Rangihaeata, along with their kinsmen of Ngāti Toa, owned the land and had not been paid for it. But similar disputes had been previously settled through negotiation, and Te Rauparaha was willing to negotiate on the Wairau land.
In January 1843 Nohorua, the older brother of Te Rauparaha, led a delegation of chiefs to Nelson to protest about British activity in the Wairau Plains. Two months later Te Rauparaha and Te Rangihaeata arrived in Nelson, urging that the issue of the land ownership be left to Land Commissioner William Spain. Based in Wellington, he had begun investigating all the claimed purchases of the New Zealand Company. Spain later wrote that during that visit, Arthur Wakefield "wished to make them a payment for the Wairau, but they positively refused to sell it, and told him they would never consent to part from it." Arthur Wakefield rejected the request to wait for Spain's enquiry, informing Te Rauparaha that if local Māori interfered with company surveyors on the land, he would lead 300 constables to arrest him. Wakefield duly despatched three parties of surveyors to the land. They were promptly warned off by local Māori, who damaged the surveyors' tools but left the men unharmed.
Te Rauparaha and Nohorua wrote to Spain on 12 May, urgently asking him to travel to the South Island to settle the company's claim to Wairau. Spain replied that he would do so when his business in Wellington was complete. A month later, with still no sign of Spain, Te Rauparaha led a party to Wairau, where they destroyed all the surveyors' equipment and shelters that had been made with products of the land. They burned down roughly-built thatched huts that contained surveying equipment. The surveyors were rounded up and sent unharmed back to Nelson.
Bolstered by a report in the Nelson Examiner newspaper of "Outrages by the Maori at Wairoo", Wakefield assembled a party of men, including newspaper editor G. R. Richardson and about 24 labourers press-ganged into service, swearing them in as special constables. Police Magistrate Augustus Thompson issued a warrant for the arrest for arson of Te Rauparaha and Te Rangihaeata. Wakefield referred to the chiefs in a letter as a pair of "travelling bullies."
Thompson commandeered the government brig, which was in Nelson at the time. On the morning of 17 June the party, its size swelled to between 49 and 60 men, including chief surveyor Frederick Tuckett and others who had joined the party after landing, approached the Māori camp. The British men were issued with cutlasses, bayonets, pistols and muskets. At the path on the other side of a stream, Te Rauparaha stood surrounded by about 90 warriors, as well as women and children. He allowed Thompson and five other men to approach him, but requested the rest of the British party to remain on their side of the stream.
Thompson refused to shake hands with Te Rauparaha and said that he had come to arrest him, not over the land issue but for burning the huts. Te Rauparaha replied that the huts had been made from rushes grown on his own land, and thus he had burnt his own property. Thompson insisted on arresting Te Rauparaha, produced a pair of handcuffs, and called out to the men on the far side of the stream, ordering them to fix bayonets and advance. As they began to cross, a shot was fired by one of the British (apparently by accident). Te Rangihaeata's wife Rongo was killed in one of the first volleys, sparking gunfire from both sides. The British retreated across the stream, scrambling up the hill under fire from the Ngāti Toa. Several people from both sides were killed.
Te Rauparaha ordered the Ngāti Toa warriors to cross the stream in pursuit. Those British who had not escaped were quickly overtaken. Wakefield called for a ceasefire and surrendered, along with Thompson, Richardson and ten others. The Maori killed two of the British immediately. Te Rangihaeata demanded utu (revenge) for the death of his wife Rongo, who was also Te Rauparaha's daughter. The Maori killed all the remaining captives, including Thompson, Samuel Cottrell, a member of the original survey team; interpreter John Brooks, and Captain Wakefield. Four Māori died and three were wounded in the incident. The British lost 22 dead and five wounded.
Historian Michael Belgrave described the British attempt to survey the land as illegal, inopportune and ultimately disastrous.
Reverberations of a reported massacre were felt as far away as England, where the New Zealand Company was almost ruined by the news of "British citizens being murdered by barbarous natives". Land sales almost halted, and it became obvious the company was being less than honest in its land purchasing tactics, and reports on the events in local newspapers were far from accurate.
In the Nelson area, settlers became increasingly nervous. One group sent a deputation to the Government complaining that those who had died had been discharging their "duty as magistrates and British subjects ... the persons by whom they were killed are murderers in the eyes of common sense and justice".
In late January or early February 1844, a month after taking up his post, incoming Governor Robert Fitzroy visited Wellington and Nelson in a bid to quell the hostility between Māori and British, particularly in the wake of the Wairau incident. So many conflicting statements had been published that it was impossible for him to decide who had been at fault. But, he immediately upbraided New Zealand Company representatives and the editor of a Wellington newspaper, The New Zealand Gazette, for their aggressive attitude towards Māori, warning that he would ensure that "not an acre, not an inch of land belonging to the natives shall be touched without their consent". He also demanded the resignation of Thompson, the magistrate who had issued the arrest warrants for the Māori chiefs, but he was killed in the action.
"When I first heard of the Wairau massacre ... I was exceedingly angry ... My first thought was to revenge the deaths of my friends, and the other Pakeha who had been killed, and for that purpose to bring many ships of war ... with many soldiers; and had I done so, you would have been sacrificed and your pa destroyed. But when I considered, I saw that the Pakeha had in the first instance been very much to blame; and I determined to come down and inquire into all the circumstances and see who was really in the wrong."
Te Rauparaha, Te Rangihaeata and other Māori present were invited to recount their version of events, while Fitzroy took notes and interrupted with further questions. He concluded the meeting by addressing the gathering again, to announce he had made his decision: "In the first place, the white men were in the wrong. They had no right to survey the land ... they had no right to build the houses on the land. As they were, then, first in the wrong, I will not avenge their deaths."
But FitzRoy, who had a background as a humanitarian, told the chiefs they had committed "a horrible crime, in murdering men who had surrendered themselves in reliance on your honour as chiefs. White men never kill their prisoners". He urged British and Māori to live peaceably, with no more bloodshed.
Settlers and the New Zealand Company were incensed by the Governor's finding, but it had been both prudent and pragmatic; Māori outnumbered settlers 900 to one. Many iwi had been amassing weapons for decades, giving them the capacity to annihilate settlements in the Wellington and Nelson areas. Fitzroy knew it was highly improbable that troops would be despatched by the British Government to wage war on the Māori or defend the settlers. FitzRoy's report was endorsed by Colonial Secretary Lord Stanley, who said the actions of the party led by Thompson and Wakefield had been "manifestly illegal, unjust and unwise", and that their deaths had occurred as a "natural and immediate sequence". William Williams, a leading Church Missionary Society missionary, also clearly apportioned blame to "our countrymen, who began with much indiscretion & gave much provocation to the natives".
The effect of the massacre and the passive reaction of Fitzroy set in train a chain of events that still rumble through the New Zealand courts today. Its immediate effect was to alarm settlers in New Plymouth, who had insecure title to land purchased under similar circumstances to Wairau. FitzRoy was very unpopular and was recalled to be replaced by Governor George Grey.
After the massacre, Te Rauparaha never returned to the Wairau Valley. He was captured in 1846 for organising an uprising in the Hutt Valley and was imprisoned on HMS Calliope in Auckland without charges being brought. Author Ranginui Walker has claimed the arrest was delayed punishment for the Wairau killings. The Ngāti Toa iwi sold the Wairau land while Te Rauparaha was held in captivity.
This rohe (area) has been the subject of a lengthy but successful land/compensation claim by the original Rangitane iwi, which had been displaced in the 1820s by Te Rauparaha's heke. The Rangitane iwi are recognised as the tangata whenua (home people). In 1944 the government investigation established that the Wairau land had never been legally sold to the settlers. Compensation of some $2 million is to be paid by the government of New Zealand.
- In 1869 the Nelson community erected a memorial at Tuamarina Cemetery to commemorate the European casualties of the incident, with their names and the occupations listed on the inscription.
- "Wairau Affray", 10 August 1844, Southern Cross, Volume 2, Issue 69, Page 2
- King 2003, p. 182.
- Burns 1989, p. 236-237.
- Burns 1989, p. 227.
- Keenan 2009, p. ?.
- Moon 2000, p. 81.
- Belich 1986, p. 21.
- Chapter Vl - Spain's Court. "History of New Zealand". New Zealand Electronic Text Centre. Retrieved 6 March 2012.
- Burns 1989, p. 227-238.
- Keenan 2009, p. 138.
- Moon 2000, p. 83.
- Moon 2000, p. 83-85.
- Burns 1989, p. 233.
- "...a list of white men present at the affray..", 25 July 1888, Marlborough Express
- Belgrave, Michael (2005). Historical Frictions: Maori Claims and Reinvented Histories. Auckland: Auckland University Press. pp. 142–143. ISBN 1-86940-320-7.
- Moon 2000, p. 90, 96.
- Moon 2000, p. 93.
- Moon 2000, p. 87-98.
- Moon 2000, p. 131.
- Moon 2000, p. 89, 94.
- Moon 2000, p. 85.
- Keenan 2009, p. 118.
- Walker, Ranginui (1990). Kaw Whawhai Tonu Matou: Struggle Without End. Auckland: Penguin. p. 105. ISBN 0-14-013240-6.
- Belgrave, Michael (2005). Historical Frictions: Maori Claims and Reinvented Histories. Auckland: Auckland University Press. p. 152. ISBN 1-86940-320-7.
- "Wairau incident memorial", New Zealand History online
- Andrews, Kevin (2009). "Wairau memorial". New Zealand Ministry for Culture and Heritage. Retrieved 16 May 2010.
- Andrews, J. L. (1999). The Wairau Massacre: Mindsets of the 1840s. (Blenheim). ISBN 0-473-06103-1.
- King, Michael (2003). The Penguin History of New Zealand. Penguin Books. ISBN 0-14-301867-1.
- Moon, Paul (2000). FitzRoy : Governor in Crisis 1843-1845. David Ling Publishing. ISBN 0-908990-70-7.
- Burns, Patricia (1989). Fatal Success: A History of the New Zealand Company (1st ed.). Auckland: Heinemann Reed. ISBN 0-7900-0011-3.
- Keenan, Danny (2009). Wars Without End : The Land Wars in Nineteenth-century New Zealand. Auckland: Penguin.
- Belich, James (1986). The New Zealand Wars and the Victorian Interpretation of Racial Conflict (1st ed.). Auckland: Penguin. ISBN 0-14-011162-X.
- Buick, T.L. (1900). Old Marlborough (reprinted 1976, Christchurch, NZ: Capper Press).
- The Wairau, in History of New Zealand by George William Rusden (1883)
- W. Carkeek, Te Rauparaha, The Wairau, National Library of New Zealand
- Temple, Philip (2002). A Sort of Conscience: The Wakefields. Auckland, New Zealand: Auckland University Press. pp. 520pp.
- T L Buick, The Wairau Incident by
- W. Carkeek, The Kapiti Coast : Māori History and Place Names