Question time is an institution in the Commonwealth Parliament and in all state parliaments. Questions to government ministers normally alternate between government members and the opposition, with the opposition going first. Questions of ministers are generally asked by their counterpart shadow ministers in the opposition, and are always asked by backbenchers on the government side. In the House of Representatives, the first question is usually asked of the Prime Minister by the Leader of the Opposition. Similar arrangements apply in the Senate. To accommodate the distribution of ministers between both chambers, ministers also take on representative roles, answering questions relating to portfolios that are not their own because the responsible minister sits in the other chamber. This allows questioners to ask questions about any government portfolio in either chamber. This normally includes the Leader of the Government in the Senate representing the Prime Minister in response to questions asked by senators about general government policy. Sometimes a government Minister will arrange for a government backbencher to "ask" a question, commonly called a Dorothy Dixer, to enable the Minister to make a political speech or otherwise score political points.
Convention allows the Prime Minister in the House, and the Leader of the Government in the Senate, to terminate question time by asking that "further questions be placed on the Notice Paper". This is not a formal motion but an indication that, even if further questions were asked, ministers would not answer them since they are not compelled to do so. It is possible in this way to prematurely terminate question time, although this is rare in the House and essentially unheard of in the Senate. During the Keating Government, the Prime Minister attempted to limit the number of questions asked in a way the Liberal Opposition disapproved of. To protest the change, the Opposition made random quorum calls through the afternoon for every question they felt they had been denied that day. In the House, question time is generally scheduled from 2pm to 3:15 pm on every sitting day; in the Senate, it generally occurs from 2pm to 3pm. Apart from divisions, it is the only time the chamber is likely to be filled.
Tactically, it is considered an important defining characteristic for an Opposition Leader to be able ask a pertinent question of the Prime Minister or Premier, or to single out perceived weak performers in the Ministry.
Interjections from both government and opposition members in the House of Representatives and the Senate are common, and broadly speaking are an accepted practice, although the Speaker of the House or the President of the Senate will intervene if interjections become too frequent, if they contain inappropriate content, or if the member interjecting is disrupting debate. Given that question time is the only time of day when all members of Parliament are in their respective chambers, the appearance of question time can be rowdy and boisterous compared to the normally sedate activity during the rest of the day.
There is a 30-second time limit for questions by the Opposition and a four-minute time limit for answers in the House of Representatives. Crossbench MPs get a time limit of 45 seconds, under what is sometimes referred to as the "Katter rule". In the Senate, a questioner may ask an initial question and two supplementary questions related to their initial question. Each question has a one-minute time limit. Answers to initial questions are limited to three minutes, and answers to supplementary questions are limited to one minute. A senator may also move to 'take note' of a minister's answer after question time, allowing questioners (generally Opposition senators) to respond to the answers provided by ministers.
It is very common for points of order to be raised during question time on the issue of relevance, as a Minister answering questions will normally attempt to redirect the answer to an attack on their opponents. However, as long as the Minister is talking on the general subject of the matter raised in the question, it is usually considered relevant to the question, even if it does not address the specific issue raised in the question at all.
State Parliaments adopt similar practices to the federal Parliament.