Malcolm Turnbull has conceded the scale and frequency of terrorist attacks feels like war, but has assured Australians they are safe, and expressed every confidence that in the end, civilisation would prevail over what he branded blasphemy against Islam by godless terrorists.

Fresh from emergency phone talks with the head of ASIO, Duncan Lewis, the Australian Federal Police Commissioner Andrew Colvin, and the National Security Coordinator, Greg Moriarty, Mr Turnbull said the terror alert level would remain on "High", but counselled Australians to be confident that their police and security services would protect them.

High means an attack on Australian soil is considered likely.

In his strongest comments since Friday night's coordinated attacks in Paris, Mr Turnbull left open the prospect of a greater Australian commitment in the war against Islamic State in Syria and Iraq. He said Australia could also consider involvement in an international peace-keeping force if the situation in Syria could be stabilised.

Mr Turnbull said Australians should also have confidence in the rigour of the nation's immigration screening program, advising that he had discussed the possibility that terrorists could hide among asylum seeker populations with Mr Lewis and Mr Colvin.

That came as reports emerged that one of the Paris shooters had entered Europe via Greece as a refugee.

Asked if he agreed with the comments of French President Francois Hollande that his country and the West were at war with terrorism, Mr Turnbull was frank.

"Well, it's guns and bombs, yes, it does look like a war, but it is - we have to recognise that the resources, the strength of our states, of our nations, are so much greater than those of the terrorists," he said nearing the end of gruelling 23-hour day of talks with foreign leaders and Australian security officials.

However, Mr Turnbull, who is in Turkey for the world's premier international leadership forum, the G20, said he was hopeful that a political solution would eventually be struck because it was the only way to stabilise Syria.

"It's important to remember that while the issue of security, the issue of terrorism will be a major issue, taking a considerable amount of attention here at the G20, we also will be focusing, as we should, as every government should, on growing our economies … strong economic growth is absolutely critical."

Australia would still attend the upcoming climate change conference, which was expected to go ahead in Paris in November despite the attacks, he said.

The prime minister said he had spoken to 19-year-old Hobart woman Emily Grace Parkinson, who was recovering from emergency surgery in a Parisian hospital after being shot in the hip by Islamists on Friday – one of nearly 500 people either injured or killed in the barbarous coordinated attacks on seven target sites.

The French tragedy has stunned the world and shaken the major powers into action with US Secretary of State John Kerry and his Russian counterpart Sergey Lavrov leading several other foreign ministers to agree to a draft timetable for power sharing in Syria once IS is defeated or at least marginalised.

In a sign of the potential at least for progress out of tragedy, the countries involved in those Vienna talks included strong regional opponents such as Iran and Saudi Arabia.

"The events in Paris underscore the threat that Daesh poses to all of us," Mr Kerry told reporters.

Under the terms of the arrangement, negotiations would commence by the start of next year between the existing Syrian government of Bashar al-Assad, and several opposition groups.

That is a major advance in itself as the Syrian conflict, as Mr Turnbull noted from the resort town of Antalya where the G20 is being staged, has become a "proxy" war of sorts with the Russians backing Assad, despite his record as a murderous dictator and war criminal, and the Americans backing Syrian rebel forces including the Free Syrian Army.

Mr Turnbull said the discussion in Vienna "appeared to be promising" adding "there will need to be a political solution".

"Once that can be achieved, once there is a greater unity of purpose, it will be less challenging to defeat Daesh," he said.

Tony Abbott has raised the danger of terrorists infiltrating Australia as refugees, but Mr Turnbull hosed down such speculation.

"While there have been some exceptions, the history of terrorist activities in Australia and people of concern in this area is very much for the most part, second and third-generation Australians. So the screening of refugees of the humanitarian intake has been very careful," he said.

President Hollande has declared the attacks as an "act of war" and said hours after the attack on the Bataclan theatre: "We are going to fight and our fight will be merciless."

Mr Turnbull said that Australia was "the most successful multicultural nation in the world" because Australians were united in defending its value in freedom.