A 29-year-old man has been charged with assaulting South Australian Deputy Premier Kevin Foley in November.

The incident happened outside the Marble Bar in Adelaide's Waymouth Street in the city early in the morning on November 28.

Detectives from the State Protective Security Branch say the man is from Rosewater in Adelaide's north-west.

He has been given bail to appear in the Adelaide Magistrates Court later this month.

Just after the assault, Mr Foley had said he was in the area because he was attending a Christmas function earlier at suburban Norwood.

He said just before he was bashed in the face, he helped a person in the street nearby.

He told reporters the attack was unprovoked.

Around two weeks after the assault, police released CCTV footage of two people who may have witnessed the attack.

Mr Foley is the second member of the Labor Government to be assaulted in public.

Premier Mike Rann was hit with a rolled-up magazine in 2009 by a man who claimed the Premier had had an affair with his wife, an allegation Mr Rann denied.