Federal MPs will sit for four hours less each week than those in the last parliament after the government used its numbers to cut the work day.
Instead of sitting until 9.30pm, the House of Representatives will adjourn at 8pm on Mondays and Tuesdays.
It follows changes made in the first sitting week that moved the starting time back from 9am to 9.30am on Wednesday and Thursday.
Opposition business manager Tony Burke accused the government of changing the rules because it did not like varied voices in the chamber.
The amendment follows embarrassing losses on the floor of parliament during the first sitting week when several coalition MPs, including three ministers, left Canberra early.
Mr Burke said the government was trying to avoid that happening again by stopping the chamber sitting.
"If a school has a problem with truancy, they don't propose to fix it by just shutting the school down," he told parliament on Tuesday.
But Leader of the House Christopher Pyne said there would be more hours in the Federation Chamber - or the spillover chamber - to make up for the change.
Earlier, the government used its numbers to add a rule that allows a vote to be called again if "through misadventure" caused by a member being accidentally absent or some similar incident".
Labor said that rule was also designed to mitigate the risk of embarrassing vote losses.
"The answer is not to change the rules, the answer is to turn up to work," Mr Burke said.
But Mr Pyne insists "misadventure" is by convention used to describe an MP who did not mean to be absent - not someone who had left parliament early.
For example, he said, if someone got stuck in the facilities in the parliament.
Independent Bob Katter also won support to change give members not aligned with a major party to ask 45-second questions in question time instead of 30.
