Ed Husic said the revised plan raises questions about security, workforce shortages and nuclear waste as Peter Garrett launches a crowdfunded inquiry.
On Tuesday, Labor MP Ed Husic questioned the AUKUS pact after the United States announced Australia would receive three used Virginia-class submarines, rather than the originally planned mix.
Defence Minister Richard Marles met with U.S. War Secretary Pete Hegseth in Singapore on Saturday, where they reaffirmed AUKUS while arguing three used submarines would "streamline" an "incredibly complicated" deal.
Former Labor minister Peter Garrett and former defence force chief Chris Barrie announced a crowd-funded "people's inquiry" into the $368 billion project, labeling it "controversial and secretive."
Shadow Defence Minister James Paterson accused Husic of launching a "full-on Labor revolt," challenging the government to maintain unity on its signature defence policy.
Husic expressed concerns about sluggish American production rates and potential demands from President Donald Trump, urging the government to develop a "Plan B" for the submarines.