A specialist on international relations says Tony Abbott's pledge to support the United States in its efforts to deal with Syria marks a change in position since the federal election.

President Barack Obama and the Prime Minister elect have spoken on the phone and discussed ways to further strengthen the US-Australia alliance.

A statement from the White House says the discussion included Russia's proposal regarding Syria's chemical weapons and the stationing of two-and-a-half-thousand US Marines in Darwin.

The statement said the two leaders shared "grave concern" over charges that Syrian President Bashar al-Assad used chemical weapons.

Deakin University's Scott Burchill says Mr Abbott is now offering greater support to the US since the phone conversation.

He told Greg Dyett, Mr Abbott's pledge of strong diplomatic and political support is in keeping with the Australia-US alliance, but is an interesting change of position on Mr Abbott's part.