Australian Greens Leader Christine Milne says Tony Abbott should level with the men and women of Australia's Defence Force when he farewells them tomorrow on an open-ended mission to Iraq.

"When you ask young men and women to put their lives on the line, you should be honest enough to tell them that you're committing them to war," said Senator Milne.

"This has been mission creep from the start. Australia is getting itself into an open-ended war.

As the extent of Australia's military involvement in Iraq remains unclear, Greens Leader Christine Milne explains why Australia should join many other democracies in giving the national parliament the final say on whether we go to war.

As the situation in Iraq deteriorates, Australian Greens Leader Christine Milne wants to give Parliament the authority to debate and vote on any military deployments, and is calling for Labor's support.

"Unlike many other democratic countries, Australia's military can be deployed overseas without any discussion or decision in the Parliament. This must change," said Senator Milne.

With reports coming out of the United States of possible Australian military involvement in Iraq and Syria, Greens Leader Christine Milne says it is essential that any decision to deploy our military is brought to the parliament.

"It is essential that PM Abbott commits immediately to bring any debate about the deployment of Australian military to the parliament for debate," Greens Leader Christine Milne said.

The Federal Government must rule out allowing US military spy drones to be based on Australia's Cocos Islands, the Greens said today.

Greens spokesperson assisting on Defence, Senator for Western Australia Scott Ludlam, said the Government needs to respond decisively to reports that the US is considering the use of the islands off the north-west coast for surveillance drones and other spy aircraft.