SCOTT Morrison is reportedly preparing to swing an axe through the public service with several department heads set for the chopping block.

The prime minister is expected to slash the number of government departments in an effort to cut bureaucratic red tape, The Australian reports.

Up to five department secretaries are expected to sacked in the purge.

"Obviously the public service has a very significant role to play and there needs to be stability within the public service," Labor deputy leader Richard Marles told Sky News on Thursday.

"I think it's really important - particularly at this time, given all the challenges that we're facing - that the government is managing the public service in a way which maintains stability and ultimately maintains morale."

Mr Morrison said in a speech in August the Australian Public Service needed to "evolve" and in some cases "conventional wisdom needs to be challenged".

He also called for "congestion busting", to encourage new ideas on how to improve services.

"I am concerned that just over a quarter of the APS does not really feel they can impact what's going on," he said at the time.

"This concerns me. I want people in the APS to feel they can make a contribution. I don't want you to be shut out. You need to feel that you can make a difference. That is why you're here.

"This is a failure of public service management to enable real engagement. This is one of the things I expect to see public service leaders change."