The defence minister is being urged to haul backbencher Ed Husic into line after the Labor MP broke ranks to call for a rethink of the AUKUS nuclear submarine deal.
Mr Husic went public with his reservations about the pact following revelations Australia will only get second-hand submarines from the United States.
His comments follow Midnight Oil frontman and former Labor minister Peter Garrett announcing plans for an independent "people's inquiry" into the national security implications of AUKUS.
Mr Husic, who also questioned the deal during a private caucus meeting on Tuesday, said Australia needed to reconsider its commitment to the deal with the US and the UK because America was becoming an increasingly unreliable ally.
"You do wonder whether or not we will get the deal, even the reconfigured one that we have got," the western Sydney MP told reporters at Parliament House.
