14 February – A report is released which condemns the police rescue effort during the Newcastle earthquake.
15 February – The Reserve Bank of Australia cuts official interest rates by half a percent – a move which Federal Opposition MP John Hewson described as "blatantly playing politics".
16 February – Prime Minister Bob Hawke announces a March 24 election date.
24 June – The Victorian Government orders the closure of the Farrow Corporation building societies Pyramid, Geelong and Countrywide.
7 August – John Cain resigns as Premier of Victoria over a series of financial scandals, and is replaced by the first female premier of Victoria, Joan Kirner.
1 October – The Tasmanian Greens terminate the Labor–Green Accord after Tasmania adopts the federal government's Forests and Forest Industry Strategy.
2 October – Opera singer Dame Joan Sutherland announces her retirement.
5 October – After one hundred and fifty years, ten months and two days, The Heraldbroadsheet newspaper in Melbourne is published for the last time as a separate newspaper. Founded in 1840 as The Port Phillip Herald, it is merged with its morning tabloid sister paper The Sun News-Pictorial and the first issue of the new Herald Sun, described by owner Rupert Murdoch as "the world's first 24-hour newspaper", with morning and afternoon editions, is published on 8 October.On the same day, the 49-year-old afternoon tabloid The Daily Mirror in Sydney is published for the last time as a separate newspaper. The first edition of The Daily Telegraph-Mirror also appears on 8 October.
1 November – The Australian domestic aviation market is deregulated.
21 November – The Queensland state caucus amends the amend the Criminal Code and the Criminal Law (Sexual Offences) Act 1978–1989 to decriminalise consensual sexual activity between adult males in private.
29 November – Treasurer Paul Keating announces that Australia is experiencing an economic recession.
11 December – Media company Fairfax is placed in receivership.
27 December – WIN Television purchases Star Television just three days before Queensland is due to be aggregated, giving them the Nine Network affiliation and leaving QTV, who were going to take the Nine affiliation, with the Network Ten affiliation.
31 December – The Queensland regional television market is aggregated, with Sunshine Television Network (now Seven Queensland) taking a Seven affiliation, WIN Television taking a Nine affiliation, and QTV with the Ten affiliation.
22 January – John McEnroe is thrown out of the Australian Open Tennis Championships.[4]
27 January – Steffi Gras wins the Australian Open Tennis Championship.
Hayley Lewis wins her fourth gold medal at the Auckland Commonwealth Games.
28 January – Lisa Curry wins a gold medal at the Auckland Commonwealth Games.
30 March – First day of the Australian Track & Field Championships for the 1989–1990 season, which are held at the Olympic Park in Melbourne, Victoria. The men's 10,000 metres event was conducted at Canberra on 24 February 1990.
22 July – Allan Carman wins the men's national marathon title, clocking 2:15:17 in Brisbane, while Trudy Fenton claims the women's title in 2:44:38.
23 July – Players' draft adopted at board meeting of NSWRL.
8 September – Collingwood draws its elimination final with the West Coast Eagles. The AFL finals schedule is thrown into chaos and the Grand Final is rescheduled to be played a week later than usual. Extra time is subsequently introduced for future finals matches.
6 October – Collingwood (13.11.89) defeats Essendon (5.11.41) to win the 94th VFL/AFL premiership. It is the first premiership won under the AFL banner and Collingwood's first premiership since 1958, thereby symbolising the end of the "Colliwobbles".