Queensland Liberal MP Steve Ciobo will take over the trade portfolio in Malcolm Turnbull's shakeup of his front bench.
The prime minister on Saturday unveiled his new ministry, which includes Andrew Robb as special envoy for trade until he retires at this year's election.
The Nationals now have an extra seat in cabinet, with new deputy Nationals leader Fiona Nash and Darren Chester joining Barnaby Joyce and Nigel Scullion.
Mr Chester, a Victorian Nationals MP, takes over outgoing Deputy Prime Minister Warren Truss' portfolios of transport and infrastructure.
Fellow National Luke Hartsuyker has been dumped from the ministerial lineup.
Mr Turnbull has announced several other promotions.
"The new ministerial lineup that I'm announcing today is a dynamic team which combines youth, new talent, experience, continuity and a real sense of innovation and enterprise," Mr Turnbull told reporters in Sydney.
Mr Hartsuyker is being replaced as vocational education and skills minister by Victorian Liberal senator Scott Ryan.
New Nationals leader Barnaby Joyce will retain the agriculture and water portfolios, while his deputy, Senator Nash, will add regional development and regional communication to her rural health portfolios.
Six women are now in cabinet, with Senator Nash joining Liberals Julie Bishop, Sussan Ley, Marise Payne, Kelly O'Dwyer and Michaelia Cash.
All remaining cabinet ministers have retained their jobs, with most of the changes happening in the outer ministry and assistant ministry levels.
Among those promoted is Alan Tudge, who takes over human services, the portfolio held by Stuart Robert before he was forced out of the ministry on Friday.
Newly promoted ministers include Dan Tehan (defence materiel, veterans' services), Concetta Fierravanti-Wells (international development and the Pacific) and Matt Canavan (Northern Australia), who are now in the outer ministry.
New assistant ministers include Nationals Keith Pitt and Liberals Craig Laundy, Jane Prentice, Angus Taylor, Peter Hendy and James McGrath.
Mr Turnbull said there was a "wealth of experience in this ministerial lineup".
"This is a revitalised government and it's revitalised because of new blood, of new talent coming in."
Queensland Nationals senator Matt Canavan has moved from the back bench and will be sworn in as the minister for Northern Australia, working alongside the senior minister in that portfolio, Josh Frydenberg.
"This is a policy area of northern Australia, of northern development which is absolutely central to Australia's growth and future prosperity," Mr Turnbull said.
He said Mr Robb recommended Mr Ciobo take over the trade portfolio, but retaining Mr Robb as a special trade envoy would ensure a proper handover in the vital role.
