A woman in a black coat is then led away from the group and falls to the ground with a police officer.

Police can be heard saying "get up now", and the woman can be heard replying: "I'm trying".

A photo from after the incident appears to show Ms Thomas standing beside an officer with a swollen eye.

The witness said they saw Ms Thomas being tripped to the ground, and that she was struck in the face when officers attempted to get her to her feet.

"Several officers came over and in an attempt to help carry the individual away … that is when the strike occurred," the attendee said.

"It was very clearly a strike to the eye."