Police have reported two men for assault over an incident involving a South Australian Liberal candidate and a volunteer.

But the men who allegedly assaulted the pair say they were the ones who were attacked.

Liberal candidate Jassmine Wood and volunteer Adrian Robb were campaigning outside a supermarket in the Hindmarsh electorate in Adelaide.

They say they were approached by two men who criticised the Liberal Party's border protection policies and the confrontation turned violent.

Ms Wood says punches were thrown.

"My poor volunteer got smacked in the face and I got hit in the head at the same time and then my volunteer got pinned to the ground and punched over and over," she said.

Matt Hamon says he was shopping with his friend when he was approached by Ms Wood.

He says he began a discussion with her about asylum seekers but says he and his friend did not assault Ms Wood or Mr Robb.

Mr Hamon's friend did not want to be identified but supplied pictures he said were are of injuries inflicted by Mr Robb.

"Mr Robb, I believe his name is, several times jumper punched my friend who has quite a number of injuries to his face," Mr Hamon said.

Mr Robb denied the suggestion.

"Any suggestion that myself and the Liberal candidate would randomly attack a shopper is probably as preposterous as it sounds," he said.

The two men faced the Adelaide Magistrates Court, where the charges were dismissed.