A former waitress is expected to expand on allegations of a sexual relationship with the South Australian Premier Mike Rann in a paid television interview tonight.

Michelle Chantelois has made the claims to a Channel Seven current affairs program.

"There was sex involved," she said.

"I'm taking responsibility for my own bad behaviour and Mike Rann should take responsibility for his own bad behaviour."

Ms Chantelois is the estranged wife of Richard Phillips, the man who allegedly assaulted the Premier at a function in October.

Mr Rann has admitted to being friends with Ms Chantelois when she worked at Parliament House but his office has denied there was a sexual relationship.

The Premier says he is waiting to see tonight's interview before commenting further.

"I'm going to be making a full statement on Monday. I haven't seen the allegations," he said.

"But I will say this: What I have been told is wildly sensational."

Last month, Mr Rann said he had been stalked, attacked and received death threats.

He said he was frustrated that he was unable to "clear the air" because matters were before the police.

Mr Rann faces a state election in March.

Labor rallies

Meanwhile, Labor MPs are closing ranks behind Mr Rann, with frontbencher Tom Koutsantonis saying he has the party's full support.

"The Premier's been an excellent premier for South Australia, with record investment in rail, record investment in defence industries, $44 billion rebuilding our schools, rebuilding our hospitals," he said.

"I think he's been one of the greatest premier's South Australia's ever had and I don't think people are interested in this sort of thing."

Ms Chantelois's lawyer says his client is under enormous pressure and has considered it best for her family to deal with the issue by way of exclusive interviews.

He says his client has also spoken to a women's magazine.