Federal Labor wants to know why the government rejected a US request to boost its military involvement in the Middle East.
Defence Minister Marise Payne remained firm on Australia's existing level of assistance when asked to reconsider the country's contribution late last year.
"Australia has considered the request ... in light of the substantial contributions we are already making to train Iraqi security forces and to the air campaign," she said in a statement on Thursday.
"The government has advised Secretary Carter that our existing contributions will continue."
Opposition Leader Bill Shorten said Labor had not been told about the request from the US.
"I expect the government to reignite the bipartisanship which was traditionally expected," he told reporters in Burnie, Tasmania.
"This matter is too important for politics."
Former defence minister Kevin Andrews used news of the request to reiterate his push for ground troops to combat Islamic State militants.
"If the Americans have made a reasonable request of us, then we should be giving it the most favourable consideration," he told ABC radio on Thursday.
Mr Andrews said Ms Payne had information before her that he did not anymore.
"It's quite clear from the advice I received, and I was aware of what the American military personnel and defence leaders were suggesting, and that was for months they were suggesting that we needed forces on the ground in order to defeat ISIL," he said.
The former minister defended his decision to repeatedly speak out about his old portfolio.
"We have to speak the truth," he said.
"I'm stating my view as a humble backbench member of the parliament that has a responsibility for the country."
Independent MP Andrew Wilkie said it was a "refreshing decision" from Australia to say 'no' to the US.
"The US has taken us for granted, they've ... only had to say jump and we say how high," the former intelligence analyst told ABC radio.
Another former defence minister, Brendan Nelson, said when he was overseeing the portfolio countries were regularly asked to think about their contributions.
"On the basis of what's available in the public arena it seems like a perfectly sensible decision," he said.
