Labor leader Bill Shorten has defended his party's Abbott-style parliamentary tactics, dismissing criticism the opposition is ignoring issues more important than Barnaby Joyce.
Labor on Wednesday moved a seventh consecutive question time suspension motion - breaking a record Tony Abbott set as opposition leader - as it pursued the eligibility of the deputy prime minister to sit in parliament.
"Defending the integrity of Parliament is not a small issue," Mr Shorten told ABC radio.
Referring Mr Joyce to the High Court was unprecedented, he said.
"We are in unchartered waters here."
Labor argues there are serious practical issues with Mr Joyce serving as acting prime minister while Malcolm Turnbull attends the Pacific Islands Forum in Samoa on Friday.
Opposition frontbencher Anthony Albanese says it would undermine every government decision.
"I've served as acting prime minister... what the Australian people know is that those decisions shouldn't be made under a cloud," he told reporters.
