As prime minister, Mr Abbott committed the Royal Australian Air Force to the US-led strikes over Iraq and Syria. But Mr Abbott conceded the strategy would be of limited effect.

"The United States and its allies, including Britain and Australia, have launched air strikes against this would-be terrorist empire. We've helped to contain its advance in Iraq but we haven't defeated it because it can't be defeated without more effective local forces on the ground," he said.

Thatcher's Falklands response

"Everyone should recoil from an escalating air campaign, perhaps with Western special forces on the ground as well as trainers, in a part of the world that's such a witch's brew of danger and complexity and where nothing ever has a happy ending.

"Yet as Margaret Thatcher so clearly understood over the Falklands: those that won't use decisive force, where needed, end up being dictated to by those who will."

Tony Abbott at the Margaret Thatcher Centre where he said people who won't use decisive force end up being dictated to by those who will. Julian Andrews

Mr Abbott said the US, Britain and Australia had to stay committed to the region and the fight against Islamic State because "leaving anywhere, even Syria, to the collective determination of Russia, Iran and Daesh should be too horrible to contemplate".

"That's why it's a pity that the recent UN leaders' week summit was solely about countering violent extremism – which everyone agrees involves working with Muslim communities – and not about dealing much more effectively with the caliphate that's now the most potent inspiration for it."


Labor leader Bill Shorten said Iranian and Russian influence in Syria was already dominant and Australia should be careful about how much it gets involved.

"I think it's very difficult at great distance for Australia or some other countries to say they've got the answers in Syria," Mr Shorten said.

"The challenge is, how do we help the victims of Syria."

Mr Abbott's speech stirred controversy globally because his advice to Europe to shut its borders to refugees and others arriving from the conflict, saying it's "wholesome instinct" to allow in people fleeing the conflict "is leading much of Europe into catastrophic error".

"In Europe, as with Australia, people claiming asylum – invariably – have crossed not one border but many; and are no longer fleeing in fear but are contracting in hope with people smugglers," he said.

"However desperate, almost by definition, they are economic migrants because they had already escaped persecution when they decided to move again.

"Our moral obligation is to receive people fleeing for their lives. It's not to provide permanent residency to anyone and everyone who would rather live in a prosperous Western country than their own."