Mihaka has been involved in a number of campaigns regarding Māori rights, and was involved in the Bastion Point land dispute. His 1979 attempts to use Māori language in court were appealed to the Court of Appeal and were the trigger for the 1986 Waitangi Tribunal ruling that the government should introduce legislation making it an official language of New Zealand. He has written two books on Māori issues. He is most known, however, for performing an act of whakapohane (baring his buttocks, a traditional Māori insult) to Diana, Princess of Wales and Charles, Prince of Wales in 1983. Some sources claim this was actually directed at the Queen herself, however, this is likely confused with a later incident in 1986 in which Mihaka was arrested for driving a van with an image of whakapohane in the vicinity of a royal motorcade; on that occasion, he was charged with dangerous driving.
 New Zealand electorate campaigns
He stood as an independent candidate for the Te Tai Tokerau parliamentary seat in the 1999 election, winning 1.03% of the vote. In 2004, he stood in the Te Tai Hauauru by-election, challenging the incumbent Tariana Turia. Mihaka stood as the candidate for the Aotearoa Legalise Cannabis Party, the only party other than Turia's Māori Party to contest the by-election. Mihaka claimed that the drugs issue was of greater importance to Māori than the foreshore and seabed controversy, which Turia largely focused on. In the by-election, Mihaka placed a distant second, winning 2.52% of the vote compared to Turia's 92.74%. He did, however, place above the four independent candidates.
- "Maori protester jailed for abusing judge". stuff.co.nz. 2011 [last update]. Retrieved 17 July 2011. "Veteran Maori protester Te Ringa Mangu Nathan (Dun) Mihaka has lost his appeal against a sentence of 28 days imprisonment for calling a judge an 'arsehole'."
- "Waitangi Tribunal claim". 10 July 2007. Retrieved 2008-04-28.
- "A place still for a professional stirrer". Retrieved 2008-04-28.
- Perkins, Emily (July 19, 2002). "My Commonwealth". The Guardian (London). Retrieved 2008-04-28.
- "New Zealand Police Stop Royal Convoy Protester". The New York Times. February 28, 1986. Retrieved 2008-04-28.