Coalition leader Tony Abbott took a very cautious approach towards international action against Syria on Friday, saying it was advisable to "be very careful about getting involved in a civil war between two deeply unsavoury sides".

As the United States' plans for air strikes against Syria were thrown into disarray when the British parliament rejected a motion paving the way to authorising military action, Abbott said Australia did not have the capacity to take part in any international strike.

"Should any action be taken, it will be taken by countries with the capacity to do so, and Australia is not one of them," Abbott said.

He said it was important for the international community to "do what you reasonably can to uphold international standards of decency", but also "to be careful to avoid making a bad situation worse".

Kevin Rudd has said the government believes there is "overwhelming evidence" that chemical weapons have been used in Syria and "high confidence" that the Syrian regime is responsible for "this act of mass murder". But he confirmed on Friday that there had been "no request to Australia by any other country for a direct or indirect military participation in any proposed or possible military action against Syria".

Abbott pointed out that he had supported Australia's involvement in both Iraq and Afghanistan and did not "rule out future interventions in conflicts".

But he said this was "a time for cool heads, not a time for intemperate action or for Australia to exaggerate its role" and that it was important to wait to see the conclusions of UN inspectors investigating the use of chemical weapons in Syria.

Rudd had accused Abbott of not having the "temperament" for international diplomacy.

"I sometimes question, I really do question having known Mr Abbott for a long, long time, whether he really has the temperament for that sort of thing," Rudd claimed earlier this week.

"You've got to sit back, think calmly, reflect and then work through what the best decision is. And temperament, judgment and experience are quite important."

Both Rudd and Abbott have received top-level bureaucratic briefings on the Syria crisis during the election campaign.