A Federal MP who spoke out against the escalation of Australia's military involvement in Iraq says she was sent a death threat on Twitter.

Melissa Parke, a former human rights lawyer and now Labor MP in Western Australia, made the revelation in a speech to Parliament.

"Last week on Twitter a person called for my execution for treason because I had questioned the government's rapid escalation of our new involvement in Iraq from a purely humanitarian mission to one where we appear to be joining the US in an open-ended fight against IS," Ms Parke began.

"A call for my execution may be extreme, but it demonstrates how the beating of the drums of war and the hysteria this generates inevitably prevent the kind of calm, serious and rational discussion that is called for when decisions are being made to commit Australians overseas to kill and potentially to be killed."

Ms Parke has been a lone voice among the major parties in questioning the rapid nature of Australia's switch from humanitarian aid to military support for the US-led mission, while other MPs have questioned the government's political tactic in illuminating national security issues at the expense of budget discussions.

She said the challenges in Iraq were "never going to be resolved" by "approaching this group as a death cult" and described the plan of "arming supposed moderates" in Syria as "delusional".

Ms Parke also criticised Australia's decision not to seek UN authorisation for any military action in Iraq, something the Prime Minister Tony Abbott has said has not been necessary because the government has directly asked coalition countries to intervene.

"One has to ask why on earth the UN was not our first port of call, especially at a time when we occupy a valuable seat on the UN Security Council . . . It has been a matter of great surprise and disappointment to me that the government has not engaged with the UN before committing special forces and equipment to the so-called coalition of the concerned," Ms Parke told Parliament.

"In my view we should be endeavouring to ensure that there is a broad-based international partnership engaging moderate Islamic states such as Indonesia and Malaysia as well as neighbouring Middle Eastern states such as Jordan and Turkey, under the auspices of the UN, to address the very real humanitarian and human security issues that are at the heart of the current problem.

"There is an enormous danger in moving so quickly that these questions are not examined and when the possible consequences are not thought through, anticipated and planned for."

She said that she did not oppose some role in protecting citizens from the Islamic State (also known as ISIL) militants, but said any conduct had to be in accordance with the international rule of law and based on "humanitarian objectives".

"I am concerned too about the increased security risk to Australians everywhere as a result of our involvement in further action in Iraq," she said.

Overnight Islamic State has posted an exhortation online urging its supporters to kill non-believing Australians by any means necessary.

The Abbott government says the threat is genuine and is being taken seriously.

Ms Parke has previously voiced her concerns about Australia's involvement in Iraq.

Both the Prime Minister and Labor Leader Bill Shorten said at the time that they understood Australians would feel anxious about Australia's role but insisted it was necessary because of the threat of a domestic terror attack, carried out at the urgings of IS.