Prime Minister Scott Morrison will undertake a major overhaul of the public sector, putting 280,000 public servants on notice, while warning his ministers to do their job and not allow "a policy leadership vacuum to be created".

In a speech designed to set expectations for his second term, Mr Morrison will put a target on under-performing ministers who are "captive of their department" and fail to set the agenda.

"That is not a reflection on the department, but on the minister. It speaks to a minister not driving their policy agenda," he will tell hundreds of public servants in Parliament's great hall on Monday.

Comparing the relationship between ministers and the public service to bacon and eggs, Mr Morrison will urge the public service to provide frank advice and challenge conventional wisdom, while acknowledging that ministers have the final say in a democracy.