Casual vacancies in the Australian Parliament

Disqualification

A member will be disqualified if they are found to have been ineligible for election, or become ineligible to sit, because they:

A member will also be disqualified if they:

Resignation

A member of the House of Representatives may resign by tendering the resignation to the Speaker, as required by section 37 of the Australian Constitution, or in the absence of the Speaker to the Governor-General. Similarly, a senator would tender the resignation to the President of the Senate or in the absence of the President to the Governor-General, as required by section 19 of the Constitution.

How a casual vacancy is filled

Casual vacancies are handled in different ways, depending on the house concerned.

States

When a Senate seat representing one of the six states becomes vacant, Section 15 of the Australian Constitution requires the parliament of the relevant state to choose a replacement. This is done in a joint sitting of the upper and lower houses (except for Queensland, which has a unicameral parliament). In the event that the state parliament is not in session, the Governor of the state (acting on the advice of the state's executive council) may appoint the replacement, but such an appointment lapses if it is not confirmed by a joint sitting within 14 days after the beginning of the next session of the state parliament.

Prior to 29 July 1977, it was an established convention, but not a constitutional requirement, that the state parliament choose (or the governor appoint) a replacement from the same political party as their predecessor. It had also been the practice for the relevant party to provide a list of suitable names to the state premier, and for the state parliament to make the choice. In 1975, both these conventions were breached - in the former case, twice.

On 9 February 1975, the New South Wales Labor Senator Lionel Murphy resigned from the Senate to take up an appointment as a judge of the High Court of Australia. On 27 February, the NSW Liberal Premier Tom Lewis appointed Cleaver Bunton, a former long-serving Mayor of Albury, who was not affiliated with any political party. Bunton sat as an independent senator.

On 30 June 1975, the Queensland Labor Senator Bertie Milliner died suddenly. The Labor Party gave only one replacement name to the Country Party Queensland Premier Joh Bjelke-Petersen - that of Mal Colston. However, on 3 September, at Bjelke-Petersen's instigation, the Parliament of Queensland appointed Albert Field to the vacancy. Although he had been a member of the Labor Party for 30 years, Field was now openly critical of the Labor government of Gough Whitlam, and he was immediately expelled from the party for accepting the appointment. Field took his seat in the Senate as an independent. However, there were doubts as to his constitutional eligibility to sit at all. Although he had resigned from the Queensland Department of Education the day before he was appointed, the Education Act (Qld) required three weeks notice of resignation, and it was arguable that he was therefore still in Crown service (this technicality had been ignored many times in the past). The Labor Party immediately challenged Field's appointment in the High Court, and he was on leave from the Senate from 1 October for the remainder of his short-lived term, which ended when the parliament was dissolved on 11 November.

On 21 May 1977, a referendum was held on the question of whether the Constitution should be changed to require future Senate casual vacancies to be filled by a member of the party represented by the former senator at the time of their election, if the state parliament chooses to fill the vacancy. The referendum was passed and came into effect on 29 July 1977. Where a senator had been elected representing a certain party, and changed allegiances to a different party mid-term, and then died or resigned, the replacement senator would be a person representing the first party. This was first implemented when Senator Steele Hall, who at the time of his election represented the Liberal Movement but had later changed to the Liberal Party of Australia, resigned and was replaced by Janine Haines. She represented the Australian Democrats and was chosen because the Liberal Movement had merged with the Democrats.

Territories

When a Senate seat representing the Australian Capital Territory (ACT) or the Northern Territory (NT) becomes vacant, the replacement senator is chosen by the ACT Legislative Assembly or the NT Legislative Assembly, under section 44 of the Commonwealth Electoral Act 1918. Where the Assembly is not in session, the choice is made by the Chief Minister of the ACT or the Administrator of the NT, as the case may be. This process was used for the first time on 18 February 2003, when Gary Humphries was chosen by the ACT Legislative Assembly to replace Margaret Reid, who had resigned from the Senate on 14 February.

Prior to the ACT gaining self-government in 1989, ACT and NT casual Senate vacancies were the subject of a different law: section 9 of the Senate (Representation of Territories) Act 1973, as amended by the Senate (Representation of Territories) Amendment Act 1980. Under this provision, the replacement senator was elected by a joint sitting of both houses of the Federal Parliament. This only ever occurred twice:

This provision would still be used to fill a casual vacancy in the representation of any external territory, in the event that such a territory ever gained separate Senate representation.

House of Representatives

Casual vacancies in the House of Representatives are filled by a by-election. There is no constitutional requirement for a by-election to be held within any particular time, or at all. When a general election is expected within a relatively short time, it has often been the practice not to hold a by-election. This has been justified on the grounds that: (a) the electors of the seat in question should not be burdened with voting twice within a short period of time, when their views are hardly likely to change significantly in that time; and (b) the cost of holding a by-election is considerable, and it is ultimately the taxpayers who bear the cost.

If the Speaker considers it appropriate to hold a by-election, he or she consults with the Australian Electoral Commission as to the suitability of various dates, invites comments from the various party leaders about the proposed dates, makes the final choice, and issues the writ.

At least 33 days must elapse between the moment the Speaker issues a writ and the date of a by-election, and the Speaker cannot issue the writ until receipt of a formal letter of resignation. A by-election must take place on a Saturday.

In the event that since the previous general election there has been a re-distribution that has altered the boundaries of the division in question, the boundaries as at the original election still apply, but only those electors enrolled for that division at the time of the by-election are permitted, and required, to vote.