Australia swears in new PM Turnbull

Malcolm Turnbull has been sworn in as Australia`s new prime minister, after Tony Abbott was ousted by his party in a leadership challenge.

Mr Abbott on Tuesday said his removal was "tough" but pledged to "make this change as easy as I can".

As he prepared to take office, Mr Turnbull said it was "the most exciting time to be an Australian".

Mr Turnbull, communications minister under Mr Abbott, is Australia`s fourth prime minister since 2013.

"I`m filled with optimism and we will be setting out in the weeks ahead and the months ahead more of those foundations that will ensure our prosperity in the years ahead," he told journalists.

He is expected to preside over a meeting of Liberal MPs on Tuesday morning and then hold a meeting of the joint Liberal-National coalition parties.