Public service chief John Lloyd quits

One of Australia's most senior bureaucrats has resigned after questions were raised about whether he breached the public service code of conduct.

Senior bureaucrat John Lloyd has resigned amid concerns he breached the code of conduct. (AAP)

Malcolm Turnbull isn't saying whether an investigation will continue now that one Australia's most senior bureaucrats has resigned following months of scrutiny over emails sent to a right-wing think tank.

Australian Public Service Commissioner John Lloyd, who will finish in the role on August 8, advised the governor-general of his intention to stand down on Monday, following months of scrutiny.

The commissioner was a director with the Institute of Public Affairs before being appointed to his role.

A series of emails released under freedom of information showed Mr Lloyd had sent on to the IPA examples of public service employment conditions the think tank could argue were overly generous.

Mr Lloyd said it was publicly available information from enterprise bargaining agreements and he was passing them on to the IPA's John Roskam in a personal capacity.

"We thank him for his service," the prime minister told reporters at Trangie in NSW.

Mr Turnbull said work would begin on finding a replacement.

Asked if any further investigation was needed, Mr Turnbull responded: "That's all I've got to say."

A Senate estimates committee heard an allegation against Mr Lloyd was received by the Department of Prime Minister and Cabinet secretary Martin Parkinson on December 13 and on January 11.

It was sent to the Merit Protection Commissioner, whose role is to inquire into breaches of the public service code of conduct.

The federal opposition has questioned Mr Lloyd's impartiality.

"It was inevitable that Mr Lloyd was going to have to resign," Labor senator Murray Watt said.

The Community and Public Sector Union was pleased to see the back of Mr Lloyd.

"'Mr Lloyd used his position to promote his ideological preoccupations, which has had a terrible effect on staff and on the ability of the (Australian Public Service) to provide critical services to the public," national secretary Nadine Flood said.