Prime Minister Kevin Rudd will take a break in his election campaigning to return to Canberra for a briefing on the crisis in Syria.

Mr Rudd told reporters in Sydney he'll be working with officials on any possible Australian response.

"It's important we establish all facts first," he said.

Opposition Leader Tony Abbott will also receive a security briefing, which is consistent with caretaker conventions, Mr Rudd said.

On Friday, Mr Rudd spoke on the phone to UN Secretary General Ban Ki Moon about actions in the UN Security Council.

He's also discussed the issue with US ambassador to Australia Jeff Bleich.

Overnight, US President Barack Obama has said allegations of a new chemical weapons attack by government forces on Syrian civilians were of "grave concern".

"I've noted carefully what President Obama has said as this recent event is one which he and the government of the United states is viewing with great concern," Mr Rudd said.

"The Australian government views this development with equal concern."

The prime minister said that in his discussions with Ban Ki Moon the pair had discussed issues being considered by the security council, such as whether chemical weapons had been used, who used them, and whether they would be used again.

"These are serious matters for the entire international community," he said.

In an interview with CNN broadcast on Friday, Obama said allegations of a new chemical weapons attack by government forces on Syrian civilians were of "grave concern".

But he also pointed out obstacles to US military action, a year after warning that the use of chemical arms in the vicious Syrian conflict would cross a US "red line".

In the US, CBS News is reporting that it has been told the Pentagon is making the initial preparations for a cruise missile attack on Syrian government forces.

"We say "initial preparations" because such an attack won't happen until the president gives the green light," the report says.

Mr Rudd said his first responsibility as prime minister is to inform the Australian people that major events unfolding in the international community.

His second is to say "these are of great concern to the united states and to ourselves."

After his security briefing on Saturday the government will look carefully at who is responsible for the attacks in Syria and if further attacks could occur.

"When you are talking about the use of weapons of mass destruction potentially against large civilian concentrations this is a matter of concern for all decent human beings and of concern for our future," he said.