Section 22 of the Constitution provides:
Until the Parliament otherwise provides, the presence of at least one-third of the whole number of the senators shall be necessary to constitute a meeting of the Senate for the exercise of its powers.
By the Senate (Quorum) Act 1991, which was introduced in accordance with a recommendation of the Senate Select Committee on Legislation Procedures in 1988, the quorum of the Senate was altered to one quarter of the senators, that is, 19 out of 76 senators.
The standing orders of the Senate contain provisions to ensure that a quorum is kept during a sitting of the Senate.
If a quorum is not present when the President takes the chair at the beginning of a sitting, the bells are rung for a further five minutes, and if a quorum is not then present, the President adjourns the Senate till the next sitting. A senator present at this time is not allowed to leave the chamber while a quorum is being formed.
At any time during a sitting, a senator may draw attention to the lack of a quorum, and for that purpose may interrupt a senator who is speaking. The bells are then rung for four minutes, and if a quorum is still not present the President adjourns the Senate till the next sitting. The doors remain unlocked after the bells have been rung and when the senators are being counted. A senator who enters the chamber at that stage may be counted for the purpose of a quorum, but not one who enters after the President has finally declared that a quorum is not present.
If a division reveals that a quorum is not present, the President adjourns the Senate till the next sitting, and no decision is taken as a result of the division.
If attention is drawn to the lack of a quorum in committee of the whole, and if a quorum is still not present after the bells have been rung for four minutes, or if a division in the committee reveals the lack of a quorum, the Chair of Committees leaves the chair and reports to the Senate. When that report is made the bells are rung for four minutes, and if a quorum is not then present the President adjourns the Senate till the next sitting day.
A senator present in the chamber may not leave the chamber while a quorum is being formed. A senator who leaves or attempts to leave the chamber contrary to this standing order may be required by the chair to return.
If a quorum is called for when a senator is speaking, the time taken to form a quorum does not come out of the senator’s speaking time. Nor does it reduce the time for a debate unless the Senate is operating under a limitation of debate under standing order 142.
If the Senate is adjourned for lack of a quorum, which is called a “count-out”, the names of the senators present are recorded in the Journals.
Occasionally it is suggested that the ability of a senator to call attention to the lack of a quorum should be restricted, because the frequent use of that procedure may disrupt the transaction of business. The requirement for a quorum has been virtually eliminated in the British House of Commons for this reason. In view of the explicit terms of section 22 of the Constitution, however, any restriction on the right of a senator to call attention to the absence of a quorum may be regarded as unconstitutional, as a procedural rule of the Senate cannot be inconsistent with the Constitution.
It is not the practice for the President to call attention to the absence of a quorum. The President must be satisfied that a quorum is present before taking the chair but, once the chair is taken, the presence of a quorum is the responsibility of the Senate.
The oftmade assertion that it is the responsibility of the government to maintain a quorum is not supported by the rules. The responsibility rests with all senators. This principle was affirmed by a resolution agreed to by the Senate on 4 October 1989.