Visiting Adelaide for the first time in months on Friday, Mr Morrison said it remained the case the federal election was due towards the end of May but a date had not been decided.

SA's poll is set for March 19, based on the state's fixed four-year election cycle.

Asked if he had spoken with Mr Marshall about the issue, Mr Morrison said there was "no need for me to talk to him".

"When we determine what an election date might be next year... I've always said it's going to be in 2022, so there's no secret there.

"It's due by about the third week in May and I'll make a determination about when that is held next year.

"If that requires that discussion, then I'll certainly have that discussion."

The PM also declined to buy into the issues facing the state Liberals, after Attorney-General Vickie Chapman stepped aside this week ahead of an ombudsman's inquiry into potential conflict-of-interest issues.

The inquiry follows her decision to reject a proposed $40 million deep sea port development on Kangaroo Island where her family owns property.

Mr Morrison said those issues were a matter for the state parliamentary party.

But he praised the premier and the state government for being the inspiration that had brought back confidence in the state.

"Steven Marshall has been the energy behind that transformation," the PM said.

"He's just getting on with the job."

Mr Marshall did not join the prime minister at his early-morning event in Adelaide, with Mr Morrison saying that was just a matter of their schedules not aligning on Friday.

Australian Associated Press