South Australian Liberal MP Sam Duluk has suspended his Liberal Party membership and vowed to stay away from Parliament, pending a police investigation into his conduct at a parliamentary Christmas party.

Key points: Sam Duluk was accused of slapping a female MP on the behind at a Christmas party

Sam Duluk was accused of slapping a female MP on the behind at a Christmas party SA Police have confirmed a man has been reported for an assault that allegedly occurred on December 13

SA Police have confirmed a man has been reported for an assault that allegedly occurred on December 13 Premier Steven Marshall said it was now a matter for police

Premier Steven Marshall today sacked Mr Duluk from the Liberal party room, describing his position as "untenable".

Mr Duluk is accused of slapping SA Best MLC Connie Bonaros on the behind and making inappropriate comments to staffers at the event at Parliament House late last year.

Police confirmed Mr Duluk will be summoned to court to face a basic assault charge.

"Earlier today, I was informed that I am the subject of a formal report made to South Australian Police regarding a Christmas event at Parliament House in December 2019," Mr Duluk said in a statement today.

"I will take leave from Parliament whilst this matter is under investigation.

Premier Steven Marshall said further incidents had been brought to his attention. ( ABC News: Lincoln Rothall )

"In the interests of the Marshall Liberal Government and the broader Liberal family, I will not attend Liberal parliamentary meetings, and I will suspend my membership of the party during the course of this investigation and pending the outcome of this matter.

"I will continue to serve my electorate of Waite to the best of my ability."

Mr Duluk's statement was released almost an hour after the Premier's comments.

In his statement earlier, Mr Marshall said he had been notified of further incidents he was not aware of, and Mr Duluk was no longer welcome in the Liberal party room.

"This afternoon I became aware of further allegations regarding incidents involving the Member for Waite, Mr Sam Duluk, and his behaviour at Parliament House on Friday 13th December 2019," Mr Marshall said.

"These incidents were not brought to my attention by Mr Duluk.

"I again make it very clear, the type of behaviour that has been publicly canvassed is completely unacceptable and falls well short of the standards expected of all Members of Parliament."

SA Best MP Connie Bonaros was allegedly assaulted by Sam Duluk. ( ABC News )

Since the allegations became public, Mr Duluk has apologised on social media and in Parliament, where he expressed his "deep regret", saying he had started a "journey of recovery", getting professional help for his alcohol use.

He was also accused of making racist and homophobic comments to people at the party.

Mr Duluk quit his position as chair of a parliamentary committee once his behaviour was revealed.

Speaker Vincent Tarzia has commissioned an inquiry through a private investigator, despite admitting he did not have any power to discipline Mr Duluk if there was a finding of wrongdoing.

'Tell him he's finished as a politician'

Earlier, deputy Labor leader Susan Close had urged the Premier "to step in".

"He's the only person who can solve this issue for the people of South Australia," she said.

Ms Franks said she was disappointed with the way the allegations had been handled. ( Facebook )

"The Premier is the only person who can impose the sanction required, which is that he needs to get Sam Duluk out of the Liberal Party and tell him he's finished as a politician.

"I'm not in a position to judge what the police will decide … I am in a position to judge that both the Premier and Sam Duluk have said the behaviour was unacceptable."

Greens MLC Tammy Franks said she was disappointed by the way the allegations had been handled by the Liberal Party.

Ms Franks said she held concerns for MPs and staff who had been "pulled through the media" against their wishes.

"That's been the only option here to get a process in place to call this parliamentarian to account," she said.

"I feel let down and angry, and I know many people in this place feel let down and angry by the lack of professionalism and appropriate supports.

"I will be speaking in Parliament about my concerns, and my understanding of what happened that night, and my disappointment in the Government's response."

Mr Marshall said Ms Bonaros had not raised any concerns with him about the handling of the incident since last December.