<P> The similar tactic of disappearing quorum (refusing to vote although physically present on the floor) was used by the minority to block votes in the United States House of Representatives until 1890 . That year, Speaker Thomas Brackett Reed ordered that members who were present but abstaining would count in the quorum . </P> <P> Section 22 and section 39 of the Constitution of Australia set the quorum for sittings of the House of Representatives and Senate at one - third of the whole number of MPs and senators, respectively, but Parliament is permitted to change the quorum for each House by ordinary legislation . </P> <P> In the House of Representatives, the quorum was amended down to one - fifth by the House of Representatives (Quorum) Act 1989, which means the quorum of the current House of 150 MPs is 30 MPs . In the senate, the quorum was amended down to one - quarter by the Senate (Quorum) Act 1991, so 19 senators is a quorum . The quorum includes the occupant of the Chair and is not reduced by the death or resignation of a member or senator . </P> <P> If at the beginning of a sitting the quorum is not met, the bells are rung for five minutes and a count is then taken; if the quorum is still not met the sitting is adjourned until the next sitting day . During the sitting, any MP or senator may draw attention to the lack of quorum in which the bells are rung for four minutes, and if a quorum is still not met the sitting is adjourned . </P>

Who can attend meetings of both houses of parliament without being a member