Senators are chosen by the people of each state and territory voting as one electorate at periodic elections. The term of a senator representing a state is 6 years, while territory senators' terms coincide with the term of the House of Representatives.
The provisions governing the qualifications of candidates for election and of senators, once elected, are contained in the Constitution and the Commonwealth Electoral Act 1918 (CEA). The purpose of these provisions is to ensure that the people who stand for, and are members of, the national Parliament are beholden to no-one but the electors as a whole and may therefore perform their duties free from undue external influence, including from the executive government, foreign governments and commercial pressures.
To stand for either House, a person must be:
- at least 18 years old; and
- an Australian citizen; and
- an elector entitled to vote or a person qualified to become an elector.
In 1901, the requirements for qualification were different, but the Constitution gave the Parliament power to change these requirements and it has done so on several occasions (see sections 16 and 34 of the Constitution and section 163 of the CEA).
A person who is a member of the House of Representatives or a state or territory legislature must resign before being eligible to stand for the Senate (see section 43 of the Constitution and section 164 of the CEA). A person may not make multiple nominations (section 165 of the CEA).
Section 44 of the Constitution provides further limitations on eligibility. A person cannot be chosen as a senator if he or she:
- is a citizen or subject of a foreign power; or
- is attainted of treason; or
- has been convicted and is under sentence, or subject to be sentenced, for an offence under Commonwealth or state law punishable by a prison sentence of 12 months or more; or
- is an undischarged bankrupt; or
- holds an office of profit under the Crown; or
- has a pecuniary interest in any agreement with the Commonwealth Public Service (except as a member of an incorporated company of more than 25 people).
Furthermore, a person convicted of certain bribery or undue influence offences is disqualified from being chosen as a senator for 2 years after the conviction (see section 386 of the CEA).
2. Disqualification of senators
The place of a senator who becomes subject to any of the grounds for disqualification in section 44 of the Constitution automatically becomes vacant. Disqualification also occurs if a senator becomes bankrupt or insolvent or if he or she takes, or agrees to take, any fee or honorarium for services to the Commonwealth or for services rendered in the Parliament on behalf of any person (see section 45 of the Constitution). A monetary penalty may apply if a person continues to sit as a senator while disqualified (see section 46 of the Constitution).
3. Determination of disqualifications
There are three methods of challenging the qualifications of a senator. Under each method, challenges are determined by the High Court.
Any person may bring an action under section 3 of the Common Informers (Parliamentary Disqualifications) Act 1975 against a senator alleged to be disqualified. This Act supersedes section 46 of the Constitution (section 4) and suits are heard in the original jurisdiction of the High Court (section 5).
Secondly, the Senate may at any time by resolution refer a question relating to the qualifications of a senator to the High Court, sitting as the Court of Disputed Returns, under section 376 of the CEA. The motion is categorised as Business of the Senate and therefore has priority over other types of business at most times (see Brief Guide No. 4–Categories of Business). The Court may declare that a senator is not qualified, or that a candidate was ineligible, and may declare that a vacancy exists. In 2017, Senators Culleton and Day were each found to have been incapable of being chosen as senators at the 2016 election following the reference of questions under this method.
The third method is under sections 353 to 357 of the CEA, which provide that the Australian Electoral Commission, or any candidate or person qualified to vote, may petition the High Court, sitting as the Court of Disputed Returns, within 40 days after the return of the writ (or, in the case of a casual vacancy, the notification of the choice or appointment) to examine the validity of the election, including the qualifications of candidates. The Court may examine the petition or refer it to a lower court. Possible outcomes include declarations that:
- a person returned as elected was not duly elected;
- a candidate not previously returned as elected is now duly elected; or
- the election is void.
4. Grounds for disqualification
The High Court has adjudicated a number of aspects of section 44 of the Constitution as it applies to both candidates and members or senators. For a candidate, the critical point is nomination, which begins the process of being chosen (Sykes v Cleary (No. 2) (1992) 176 CLR 77). To be eligible for election, a candidate must be clear of any of the grounds for disqualification at the time of nomination (Free v Kelly (No. 2) (1996) 185 CLR 296).
44(i): owes allegiance to a foreign power etc.
Paragraph 44(i) applies to a person who has formally or informally acknowledged allegiance, obedience or adherence to a foreign power and who has not withdrawn or revoked that allegiance (Nile v Wood (1988) 167 CLR 133). For these purposes, "foreign power" includes the United Kingdom (Sue v Hill (1999) 199 CLR 462). To qualify for election, it is not enough for a person to have become an Australian citizen unless that person has also taken reasonable steps to renounce foreign nationality (Sue v Hill (1999) 176 CLR 77). What amounts to reasonable steps will depend on the circumstances of the particular case (Sykes v Cleary (No. 2) (1992) 176 CLR 77).
44(ii): has been convicted and is under sentence etc.
For paragraph 44(ii) to apply, a person must have been convicted and be either serving a sentence or subject to be sentenced in relation to an offence punishable by imprisonment for one year or longer (Nile v Wood (1988) 167 CLR 133). A person is subject to be sentenced if he or she is awaiting sentencing, and also if he or she has been given a suspended sentence, subject to certain conditions being met. In Re Culleton [No 2]  HCA 4 a person against whom a warrant had been issued to attend court for sentencing was held to be "convicted and...subject to be sentenced" for a disqualifying offence. The subsequent annulment of the conviction did not prevent the operation of paragraph 44(ii).
44(iii): is an undischarged bankrupt or insolvent
Paragraph 44(iii) refers to a person who has been declared bankrupt or insolvent and who has not been discharged from that condition (Nile v Wood (1988) 167 CLR 133). A senator or member who becomes bankrupt or insolvent while serving is disqualified under paragraph 45(ii). On 23 December 2016, the Federal Court ordered the sequestration of a senator's estate (Balwyn Nominees Pty Ltd v Culleton  FCA 1578), the prima facie effect of which was to cause the vacation of his office as a senator (Culleton v Balwyn Nominees Pty Ltd  FCAFC8 at 1). The vacancy was notified after the President received documents recording the status of the senator as an undischarged bankrupt: statement to the Senate, 7 February 2017.
44(iv): holds any office of profit under the Crown
Paragraph 44(iv) refers "at least" to a person who is permanently employed by government, including at the State level. Taking leave without pay does not alter the character of that employment (Sykes v Cleary (1992) 176 CLR 77).
44(v): pecuniary interest in any agreement with the Commonwealth public service
Paragraph 44(v) refers to a person who "has any direct or indirect interest in any agreement with the Public Service of the Commonwealth". In a 1975 case, the High Court found that a senator who was a shareholder in a company that had an agreement with the Commonwealth Public Service was not disqualified. Barwick CJ, hearing the case alone, held that an agreement needed to cover a substantial period of time and be one under which the Crown could conceivably influence the contractor in relation to parliamentary affairs (Re Webster (1975) 132 CLR 270).
In Re Day [No 2]  HCA 14, however, the Court found that Webster was decided on an overly narrow reading of the provision and should not be followed. The Court found that the purpose of paragraph 44(v) extends to ensuring that members "will not seek to benefit by such agreements or to put themselves in a position where their duty to the people they represent and their own personal interests may conflict" (at ). The indirect pecuniary interest found to exist on the facts of the case sufficed for the Court to hold that Day was incapable of being chosen or of sitting as a senator.
While sections 44 and 45 refer specifically to candidates and members or senators, there are no safe grounds for concluding that they do not also apply to senators-elect (that is, senators who have been elected but whose terms have not begun).
For further information, see Chapter 6 of Odgers' Australian Senate Practice.
5. Loss of place for non-attendance
The disqualification provisions in the Constitution and the CEA safeguard members of Parliament against undue influence. A person who succumbs to undue influence may be ruled ineligible to stand or may lose his or her place. Senators can also lose their places if they fail to attend the Senate for two consecutive months without permission. A parallel provision applies to members of the House of Representatives (see sections 20 and 38 of the Constitution). These provisions safeguard electors against absentee representatives but have applied only once since Federation (Senator Ferguson, QLD, 1903).
For advice on any of the matters covered by this guide, senators or their staff should contact the Clerk of the Senate on extension 3350 or firstname.lastname@example.org.
Last reviewed: March 2018