Australia, incoming chair of the UN Security Council, has endorsed possible retaliation against Syria over the use of chemical weapons, even if the council fails to agree on action, Reuters sad.

Australia, a close ally of the United States, is due to take over the rotating leadership of the council on Sunday, a role that requires it to assist council members to reach agreement.

But Foreign Minister Bob Carr said that if it was proved the Syrian regime had used chemical weapons, the world had a mandate to respond, even if the United Nations failed to agree on such action.

The United States and its allies are gearing up for a probable military strike against Syria that could come within days and would be the most aggressive action by Western powers in Syria's two-and-a-half-year civil war.

Carr said the most important role for Australia as Security Council chair was to engage permanent council members Russia and China on their support so far for Syria.

The crisis in Syria, Carr said, had re-exposed a flaw in international governance, with the right of permanent UN Security Council members to veto any decision.