1 January - The Australian Securities Commission commences operations, replacing the National Companies and Securities Commission. The new Commission's function includes investigation and enforcement of corporate and securities law.
2 April - New South Wales Premier Nick Greiner makes an address to the National Press Club of Australia in which he criticises Federal Treasurer Paul Keating, accusing him of dragging the chain on microeconomic reform and claiming that Keating's apparent disinterest in fixing Federal-State financial relations may thwart attempts to lower inflation.
4 April - Prime Minister Bob Hawke announces that a Telecom proposal to increase the price of local phone calls by 2 cents to 24 cents and increase business charges may be accepted provided they were below the Consumer Price Index.
7 April - Prime Minister Bob Hawke rebukes Employment, Education and Training Minister John Dawkins during a Cabinet meeting over a speech he made the day before, in which he called for a review of the floating exchange rate, in direct opposition to the Government's policy on the issue. Dawkins also suggested that the Government's pursuit of low inflation may have to be sacrificed in the interests of stabilising the exchange rate. The Prime Minister warns the other ministers that they will face the same fate if they speak on issues outside their normal portfolio responsibilities.
11 April - Prime Minister Bob Hawke volunteers to give evidence to the WA Inc Royal Commission and announces that the former West Australian Premier Brian Burke will return from Ireland next week to testify to the Commission. Mr. Hawke also reverses his earlier categorical denial, given repeatedly in Parliament during the week, that there had been discussion of a gold tax at a lunch with Mr Burke, the failed merchant banker Laurie Connell, Alan Bond and others on June 15, 1987. In evidence before the Royal Commission, Laurie Connell said he received an assurance from the Prime Minister that the Government would not introduce a new gold tax, and that he subsequently donated $250,000 to the Labor Party.
15 April - The Australian Industrial Relations Commission hands down a national wage decision which will give Australia's 7 million workers a 2.5% pay rise. Federal Treasurer Paul Keating joins with the ACTU in condemning the decision which rejects the Accord agreement on wages for the first time since the Hawke Government came to power in 1983. The Commission also rejects Accord proposals for a more flexbile wage system.
17 April – The bulk carrier MV Mineral Diamond disappears of the coast of Western Australia. The vessel is believed to have been sunk during adverse conditions caused by Cyclone Fifi.
25 April - Prime Minister Bob Hawke secures a compromise agreement with the Australian Council of Trade Unions (ACTU) to end the stalemate on waterfront reform and fix a timetable for pay rises to stevedores linked to the Accord Mark VI. Mr Hawke proposes a two-year contract for waterside workers that would allow a $12-a-week rise from May 16 and further average rises of 4 per cent in exchange for new job classifications.
26 April - The jury in the Sir Leslie Thiess trial finds that the construction and mining magnate had bribed Sir Joh Bjelke-Petersen to win government contracts, as well as cheating his companies' shareholders.
Federal Treasurer Paul Keating intensifies speculation about a change of leadership of the Labor Party by saying publicly that the Labor Party could not demand to have both him and Prime Minister Bob Hawke in the Government at the time of the next election.
New South Wales Attorney-General John Dowd resigns after failing to get an assurance from Premier Nick Greiner that he would retain that position after the election.
23 May - Protesters storm Parliament House, Brisbane, angry at the Labor Caucus' approval for legislation giving Aborigines limited land rights but restricting their claims to less than 3% of Queensland.
After the secret deal emerged, Paul Keating makes his first challenge against Bob Hawke for the Australian Labor Party leadership. Hawke wins 66–44, and Keating resigns as Treasurer the same day. Brian Howe becomes Deputy Prime Minister and John Kerin becomes Treasurer. Simon Crean is promoted to the position of Primary Industry Minister.
The Federal Government’s monthly deficit blows out to more than 1.2 billion dollars.
October to December – The world’s largest blue-green algal bloom takes place on the Darling River, and after the deaths of over a thousand livestock, leads the New South Wales Government to declare a state of emergency.
20 November - After weeks of successive leaks, the full text of the Coalition's Fightback! (policy) is released, the day before its official launch. Initial reaction from business and financial interests is positive, and Labor is caught unprepared.
9 December - Queensland Opposition Leader Russell Cooper announces that he is under investigation for the funding of a trip to Hamilton Island with his wife and that he has refunded the cost of the trip. He stands down as National Party Leader and is replaced by Rob Borbidge.
15 December - Russell Cooper and Joan Sheldon announce that the Queensland Nationals and Liberals will co-operate in order to reduce the conflict over the new seats before the next election.
16 December - After a week of intense pressure, Prime Minister Bob Hawke is informed by a Button-led delegation that he no longer has the confidence of the Labor Party.
20 December – Barely a year after starting up, Compass Airlines Mk I is shut down. The shutdown is somewhat controversial, coming shortly before the peak Christmas travelling period and coming about partially as a result of debts owed to a government authority.
Cloudstreet adapted for the stage by Nick Enright and Justin Monjo, the theatrical adaptation opened in Sydney under the direction of Neil Armfield. Seasons followed in Perth, Melbourne, London, Dublin, New York and Washington, D.C.
2 January – Australian Nicole Provis loses in the Danone Women's Open Tennis Championship.
3 January – Jana Novotina is out of the Danone Women’s Open Tennis Championship.
4 January – The last remaining player Rachel McQuillan is out of the Danone Women's Open.
5 January – The Danone Women’s Open is delayed due to rain.
Greg Matthews puts Australia on top in the Third Ashes Test.
6 January – Czech player Helena Sukova wins the Danone Women's Hard Court Championship.
7 January – Hayley Lewis makes it into the finals of the World Swimming Championships.
26 January – Monica Seles becomes the youngest winner of the Australian Open Tennis Championship.
27 January – Boris Becker beats Ivan Lendl in the Australian Open Tennis Championship and takes the world's top ranking.
22 February – First day of the Australian Track & Field Championships for the 1990-1991 season, which are held at the Sydney Athletic Field in Sydney, New South Wales. The combined events were conducted in Perth on 22 and 23 March, while the relays were conducted at Hobart on 6 January 1991.
2 June – Carlton go within thirty seconds of becoming the first goalless team in the VFL/AFL since 1961 and only the second since 1921. Mark Arceri kicks a goal from a free kick with 33 seconds remaining.
3 June – England soccer team scores a one-nil victory over Australia.
21 July – Sean Quilty wins the his first men's national marathon title, clocking 2:14:59 in Brisbane, while Karen Gobby claims the women's title in 2:36:42.
22 September – Penrith defeat Canberra 19-12 to win the 84th NSWRL premiership. It is the first premiership for Penrith, who had been trying since 1967 to win one.