Scott Morrison is new Australian PM as Malcolm Turnbull ousted

Scott Morrison has become Australia's new prime minister after Malcolm Turnbull was forced out by party rivals in a bruising leadership contest.

Mr Turnbull had been under pressure from poor polling and what he described as an "insurgency" by conservative MPs.

Mr Morrison, the treasurer, won an internal ballot 45-40 over former Home Affairs Minister Peter Dutton - who had been Mr Turnbull's most vocal threat.

Mr Turnbull is the fourth Australian PM in a decade to be ousted by colleagues.

"It has been such a privilege to be the leader of this great nation. I love Australia. I love Australians," he said on Friday.

With an election looming, MPs were nervous about the government's poor opinion polling and recent by-election defeats.

Last week, a row over energy policy ignited long-existing tensions between Mr Turnbull, a moderate, and his party's conservative wing.

Mr Dutton, a conservative, then unsuccessfully challenged Mr Turnbull on Tuesday, but his narrow defeat only stoked further discord.

Mr Morrison entered the race after Mr Turnbull lost key backers. After a majority of MPs called for a leadership "spill", Mr Turnbull agreed to step down.

To further complicate matters, Mr Turnbull has signalled he would resign from parliament, which would force a by-election and potentially put the government's one-seat majority at risk and force the new premier to call early elections.

However, Mr Morrison, who was sworn in on Friday, told reporters there were no plans to do this any time soon.

His government, he said, would be in place by next week.

Mr Morrison, a former Tourism Australia official, entered parliament in 2007 and has since held three key ministerial portfolios.

Speaking to reporters after the vote on Friday, Mr Morrison said he would be working to "bring our party back together which has been bruised and battered this week" and bring the country together.

He also said dealing with a severe drought, which has hit parts of eastern Australia, would be "our most urgent and pressing need right now".

With a mixture of bemusement, anger and sheer frustration: many have described this week as one of the most chaotic in Australian political history.

In his final press briefing, Mr Turnbull called the week "madness" and thanked his colleagues for choosing Mr Morrison over Mr Dutton.

"We have so much going for us in this country. We have to be proud of it and cherish it," he said.

Mr Dutton said: "My course from here is to provide absolute loyalty to Scott Morrison, and make sure we win the election."

Foreign Minister Julie Bishop was also in the running for the leadership, but did not make it to the final round.

Hywel Griffith, BBC News in Canberra

So Australia has its 30th prime minister, but how long before the 31st?

Scott Morrison faces an enormous task not just in healing the wounds within his party, but in winning the forgiveness of the public.

Many Australians have watched on exasperated, as normal government business was suspended to settle a political feud.

Given that an election must be called by May, Mr Morrison's biggest challenge will be convincing the electorate that he should stay in power.

If he doesn't succeed, expect yet another PM by June.

The past decade has been marked by a series of leadership coups, with three other sitting prime ministers deposed by party rivals.

Not a single leader in recent times has succeeded in serving a full term as prime minister, partly because elections come around so often - every three years - two years less than in the UK.

So in recent years, prime ministers unpopular in the polls - or with their colleagues - have been swiftly sacrificed from within.

Dave Sharma, a former Australian diplomat, says "an election is always just around the corner, meaning members of parliament are forever focused on their electoral survival - and less so on the national interest".

Writing in the Sydney Morning Herald, Mr Sharma says "the steady drip of opinion polls and the relentless media cycle exacerbates the short-termism".

Under the Australian system, as in the UK, the prime minister is not directly elected by voters but is the leader of the party or coalition that can command a majority in parliament.