And in a surprise move, Joe Hockey, the Abbott-government Treasurer, has told the new Prime Minister he intends to quit the Parliament.

Announcing sweeping changes to the ministry at a press conference in Canberra on Sunday afternoon, Mr Turnbull said his would be a "21st century government and a ministry for the future".

"The changes I'm announcing are very extensive," he said.

New Treasurer Scott Morrison is one of the big winners, as is Senator Payne. The Abbott-government human services minister and New South Wales moderate jumps from the relative obscurity of the outer ministry to one of the government's most important portfolios: defence minister in a time of war.

Mr Turnbull said Mr Hockey had advised him on Sunday that he would "not be seeking a place in the new ministry and it was his intention to resign from the Parliament in due course".

"Joe has made a long and distinguished contribution to our nation's government and Parliament over many, many years. For which I thank him," Mr Turnbull said.

Victorian moderate Kelly O'Dwyer, long viewed as a rising Liberal Party star, has leap-frogged the outer ministry into cabinet as Small Business Minister, replacing Bruce Billson.

Ms O'Dwyer also takes on the role of Assistant Treasurer, which has been elevated to a cabinet position. Mr Turnbull said this makes her "the first woman to be elevated to cabinet within the Treasury portfolio," although Labor's Penny Wong was finance minister, and Liberal Helen Coonan was assistant treasurer in the Howard government when it was not a cabinet post in its own right.

Senator Payne's shock elevation comes at the direct expense of the outgoing defence minister Kevin Andrews, and former treasurer Mr Hockey who had been tipped for the role after being moved from his own spot in Tony Abbott's cabinet.

Mr Turnbull, who had been expected to at least double the number of female ministers in the cabinet, has taken the number of women in cabinet from two to five.

Senator Payne and Ms O'Dwyer are joined by Michaelia Cash, who enters cabinet as Minister for Employment, Minister for Women and Minister Assisting the Prime Minister for the Public Service.

Deputy Liberal Party leader Julie Bishop remains Foreign Minister, while Susan Ley remains Minister for Health and Minister for Sport.

Mr Hockey is the highest profile casualty in a slew of sackings and resignations that have removed several former Howard government ministers from the front bench.

Senior Abbott government ministers and former Howard government ministers Eric Abetz and Ian Macfarlane have been dumped from the frontbench.

The clean-out has allowed Mr Turnbull to move several fresh faces into the ministry and reward some of his key backers in Monday night's leadership spill.

Scott Morrison | appointed treasurer.

Christopher Pyne | industry, innovation and science.

Marise Payne | the first woman to be minister of defence. 

Michaela Cash | minister for employment, minister for women, minister assisting prime minister for public service.

Kelly O'Dwyer | appointed minister for small business and assistant treasurer.

Arthur Sinodinos | appointed cabinet secretary.

Simon Birmingham | minister for education and training.

Christian Porter | will be appointed minister for social services.

Mitch Fifield | appointed minister for communications and minister for the arts.

Josh Frydenberg | elevated to cabinet as minister for resources, energy and northern Australia.

Mattias Cormann | minister for finance.