More boots on the ground likely in IS war

America is likely to put more boots on the ground in the war against Islamic State extremists and Australia might have to make a greater contribution, a former army chief warns.

Peter Leahy penned an opinion piece for The Australian arguing that a more robust and confrontational approach from the US could be on the way and it will require Australia to review its national interests and its alignment with Washington's policies and actions.

He said president-elect Donald Trump's appointment of retired Lieutenant General Michael Flynn as national security adviser is likely to result in a call for "more troops on the ground, including a greater effort from regional countries and allies".