The situation in Syria has escalated to a point where Australia must start bombing Islamic State targets in the country, says its Federal Parliament intelligence and security committee chairman Dan Tehan.
Australian warplanes have been bombing Islamic State militants in Iraq since last year, but Prime Minister Tony Abbott has said he is not prepared to authorise them to cross the border and join US warplanes hitting targets in Syria.
But Mr Tehan said Australian airstrikes in Syria were now imperative to protect national security.
"We have the world's greatest humanitarian crisis occurring at the moment in Syria with over 9 million people displaced," the Liberal MP said.
"They're raping, they're murdering, they're pillaging and we need to stop the foreign fighter flow to the caliphate in Syria.
"We have foreign fighters from Australia still going to the caliphate, some of them, history shows, will try and return home and carry out attacks here."
Mr Abbott has never ruled out bombing Syria, but said the legal situation there was different to in Iraq, where the Baghdad government supports Australia fighting IS.
Syria's president Bashar al-Assad has condemned US air strikes on targets in Syria, saying they have helped recruit new fighters to Islamic State's cause.
Mr Tehan accepted that defeating IS would also require troops fighting on the ground, but said he was not calling for Australians to do that work.
"That is something that I think needs to be discussed in the United Nations (UN), I agree ... that we need to get some presence on the ground to help," he said.
"If you can get the UN to act and if you look at an example like Kosovo, then you can get a resolution."
Despite not wanting Australian troops on the ground, Mr Tehan said extending the airstrikes from Iraq to Syria may require more Australian personnel.
"That is the possibility, what we need to do is talk with our international allies, we need to get movement at the UN and if the request is for Australia to do more, then my view is Australia should be willing to do more," he said.
Mr Tehan said some of the aircraft conducting bombings in Iraq could also operate in Syria.
"Or, if necessary, we could look at putting additional aircraft on," he said.
Mr Tehan said he had not spoken to the Prime Minister about his call.
"This is something which, after a two-week trip as chair of the Parliamentary joint committee on intelligence and security, meeting with officials in the UK and France and the US, that I have come firmly to believe in," he said.