Malcolm Turnbull was sworn in as Australia's 29th prime minister on 15 September, a day after ousting long-time rival Tony Abbott in a party coup. Turnbull, a former investment banker and venture capitalist who previously led the Australian Republican Movement, was sworn in by Governor-General of Australia, Sir Peter Cosgrove.

"Mr Turnbull, I invite you to take the oath of office as prime minister," said Cosgrove, who is the Queen's representative in Australia and the country's head of state.

Turnball replied: "I, Malcolm Bligh Turnbull, do swear that I will well truly serve the people of Australia, the office of prime minister and that I will be faithful and bear true allegiance to Her Majesty, Queen Elizabeth II, the Queen of Australia, so help me, God."

"I now invite you to subscribe the oath of office," added Cosgrove, as both sat down to sign.

The Liberal Party voted in a secret ballot late on 14 September and ousted Abbott as the leader of the senior party in a ruling Conservative coalition in favour of Turnbull, who received 54 votes while Abbott got 44.

Turnbull's Liberal Party and its junior coalition partner the National Party won a landslide election in 2013 but Abbott was jettisoned by his party after a series of perceived policy missteps and destabilising infighting.

Turnbull had previously been unpalatable to his party's right wing because of his progressive views on climate change, same-sex marriage and making Australia a republic.

However, Abbott's dismal performance and over-reliance on slogans to sell his major policies, including a hard-line approach to refugees, wore down internal opposition to Turnbull.

Australia has in recent years been convulsed by backroom machinations and party coups that have shaken public and business confidence in government.