The Prime Minister's address to public servants at Parliament House on Monday earned positive reviews for accepting their role in advising on policy and recognising they were motivated by a desire to make a difference.

Mr Morrison's speech struck a better tone than his remarks to public service leaders in May, Australian National University public policy professor and former public service commissioner Andrew Podger said.

The Prime Minister filled in gaps left in that address and gave a "pep talk" rather than issuing a set of directions to public servants, Professor Podger said.

The speech was also valuable for showing what Mr Morrison meant by his call for "congestion busting" in the public service, a task the Prime Minister said would make dealing with government easier rather than cutting corners.

Professor Podger said many of the remarks at the Institute of Public Administration speech, including Mr Morrison's call for attention to the needs of the public instead of "special interests", were better directed elsewhere.

"That message is far more important for ministers and their advisers than public servants," the former APS commissioner said.

Mr Morrison's speech was also missing recognition of the role decisions and inaction of successive governments may have played in weakening the public service, he said.

Over-reliance on consultants, the tendency of ministerial offices to limit the public service's policy advice role, inadequate resourcing and problems with the bureaucracy's enterprise bargaining rules were among issues Mr Morrison ignored.

Professor Podger said he was disappointed with the lack of empathy shown for the poorest and least powerful in a speech that focused mostly on middle Australia.

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The timing of Mr Morrison's address, ahead of the release of the Thodey review into the public service, was also strange, he said.

"I'm surprised he felt he had to say it ahead of having a look over what the report says and ahead of releasing that report," Professor Podger said.

ANU public administration professor John Wanna said the speech was missing a statement about the job security and stature of department secretaries.

Mr Morrison could have used the comments to flag he wanted a more independent public service able to serve different governments, Professor Wanna said.

Community and Public Sector Union national secretary Nadine Flood welcomed the Prime Minister's call for improved digital services and collaboration across the public service.

However his aim for better service delivery from agencies was at odds with the Coalition's cuts to the bureaucracy, she said.

"There are some things in the Prime Minister's speech that don't match the government's own policy settings, so our members will be waiting for action on those fronts," Ms Flood said.