Cabinet papers released by the National Archives show ministers decided on May 28, 1986, to impose a mixed single-member and proportional representation system.

The ACT Council Bill provided for 10 single electorate members and nine members elected from the territory as a whole. Territories minister Gordon Scholes told cabinet he held talks with Coalition and Democrat figures to find a compromise acceptable to the Senate.

In a 1978 referendum, 63 per cent of Canberra residents rejected the proposal for self-government.

The Hawke Labor government won the 1983 election on a platform that included a commitment to self-government for the ACT.

The first election after self-government was held in March 1989 with 17 MLAs elected, including the Abolish Self-Government Coalition's Dennis Stevenson.

Labor's Rosemary Follett became Australia's first female head of government.

Later members of the Assembly were elected by the Hare-Clark proportional representation system from three multi-member electorates, replacing the modified D'Hondt method used in the first election.

Federal cabinet had wrestled with the implementation for several years.

In February 1986, cabinet's sub-committee on ACT government noted a memorandum on responsibility for state-type taxes in the ACT. It said transfer of ACT payroll tax and stamp duties to the ACT Council would have a cost to revenue of $65 million per year in 1985-86 prices but would be offset by a reduction in assistance to the ACT of the same amount.

On February 10, 1986, cabinet noted a memo on ACT self-government and that ''there would be some slippage in the timetable for introduction of the Australian Capital Territory Council Bill 1986 in view of drafting delays and the need to resolve several issues''.

At that stage, the ACT Council was to have a fixed four-year term, with 12 members to be part-time, with a full-time chairperson.

The memo said: ''The handover date of 1 January, 1987, sets an extremely tight schedule to accomplish all the necessary steps to achieve a smooth handover on the set date, including passage of legislation in the autumn sittings, development of arrangements for an holding of an election by September 1986 and also consulting with departments, authorities and non-government parties including unions and staff associations … Electoral arrangements are critical.''

In February 1986 cabinet considered provisions of the draft Australian Capital Territory Council Bill 1986.

It contained a provision for the Governor-General in Council to dissolve the ACT Council and appoint a commissioner to carry out the functions of the council if it failed to resolve deadlocks and in ''extreme emergency situations'' such as the council being ''incapable of governing effectively or it is conducting its affairs in a grossly improper manner''.

In May 1986, cabinet changed its view, adopting a compromise after opposition in the Senate, with the Democrats calling for proportional representation, which favours smaller parties. The amended legislation was to provide for a mixed single-member/proportional representation electoral system with 10 single members and nine members elected from the ACT as a whole.

Mr Scholes said in his submission the proposed amendments did not detract from the overall intent of the bill and ''substantially increase'' the possibility of Senate support.

''The general public will react favourably to an electoral compromise,'' he told ministers.

''The ACT Council Bill has passed all stages in the House of Representatives. The opposition and the Australian Democrats are opposing the bill in the Senate. The opposition is opposing the bill outright. The Democrats have proposed a range of amendments, the key one being a proportional representation electoral system.

''The main opposition to the bill is based on political self-interest.

''The 10/nine electoral system … should ensure that either of the major parties will normally gain a majority of seats and that there will be some minority party representation.

''An electoral system based fully on PR [proportional representation] is unacceptable.''

Last January, the ACT's first Labor senator, Susan Ryan, said cutting costs rather than granting democracy was the principal motive for self-government in the territory.