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.
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.
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".