Deputy Prime Minister Richard Marles has accused the coalition of treating Australia's defence with "contempt" and misleading voters on cost blowouts, including by trying hide an amount worth the entire WA state budget.
Mr Marles, who is also the defence minister, said the former Morrison government had an "abiding culture" of a failure in transparency following the release of an auditor-general review of a Defence investment program worth $134.1 billion.
He said when the former government was advised the Attack class submarine program would cost $78 billion, they told the public it would cost $50 billion, and they also undersold the figure of the Hunter class frigate program by $6 billion.
"That is not a failure of transparency, that is straight out misinformation on a grand scale," Mr Marles told parliament on Wednesday.
"That is the equivalent of trying to hide the entire state budget of Western Australia.
"The reason they did this is because those opposite were unable to deal with the hard questions about those costs."
The report found Defence's management of the Integrated Investment Program which includes new weapons, systems and infrastructure was only "partly effective" and failed to establish a framework for public reporting.
The auditor-general made six recommendations to improve Defence's governance for the management of the program, as well as its public reporting.
