Giving evidence before a committee into international armed conflict decision-making, former diplomat Dr Alison Broinowski said the decision to go to war should be more transparent and be voted on by the lower and upper houses of parliament.

The prime minister and cabinet decide when the country should go to war, without the approval of the parliament.

The president of the Australians for War Powers Reform organisation said highly classified information, which might relate to military strategy, would not need to be disclosed to all parliamentarians during a debate on making the decision to join a conflict.

"What we seek is for Australia not to repeat the mistakes that we have made in the past when troops were sent to war, without any clear understanding of why," Dr Broinowski said.

"The process should be open, transparent and public, not private.

"The national security committee of cabinet and the prime minister can discuss it, but it needs to be brought to the parliament for a debate and a vote before the commitment to war is made."

In a submission, the Defence Department has argued against making any changes to the decision-making process, warning a shift would "risk significant adverse consequences for Australia's national security interests".

The Greens remain committed to introducing war powers legislation, which would require the upper and lower houses of parliament to vote in favour of deploying defence force personnel overseas.

Australian Associated Press