MALCOLM Turnbull will have to undertake a major reshuffle of his frontbench with Andrew Robb expected to join Deputy Prime Minster Warren Truss in announcing his retirement from politics as early as Thursday.
While Mr Truss's retirement has been long anticipated, the departure of Mr Robb has come as a shock.
As Trade and Investment Minister since the 2013 election, he has been one fo the Coalition's best performers, sealing free trade deals with China, Japan and South Korea.
As well as the cabinet vacancies created by the departure of the two veterans, Mr Turnbull must also fill spots created by the loss of two junior minsters - Jamie Briggs and Mal Brough - over the summer while the future of Human Services Minister Stuart Robert is also uncertain due to a trip he made to China in 2014 as a private citizen.
An investigation into whether his trip breached the ministerial code of conduct, which is being undertaken by the secretary of Prime Minister and Cabinet, Martin Parkinson, is also expected on Thursday.
Mr Turnbull will then make a call on Mr Robert's future.
Mr Robb, who is 65 and entered Parliament with Mr Turnbull in 2004, said he has had a good political career but felt he had one more career left in him. He was eager to go back into the private sector and said "id rather do that at 65 than at 68".
"I’ve never been better shape, physically or mentally," sad Mr Robb who faced a public battle with depression during his political career.
He said the governmenrt was in good shape and had a lot of talent coming through and that made it an opportunte time to move on.
As well as presiding over the three free trade agreements, Mr Robb recently negotiated Australia's role in the Trans-Pacific Partnership.
