A witness says drinks went flying and men fell on the floor, during a gang altercation at Christchurch Hospital's ED

One person was assaulted, and another taken into custody - after tensions broke out on Wednesday night between four Mongrel Mob members.

Herald reporter, Pierre Nixon, says a witness told him the scrap broke out after a verbal disagreement between two men.

He says she reported seeing nurses rush waiting people to the other side of the room.

Nixon says she was angry about the situation, and concerned a nurse or security guard could've been seriously injured.