A man will appear in Dunedin District Court on Monday following an assault on a police officer on Saturday night.
The officer, 40, who was alone, had stopped a car. He was struck on the back of his head by a male passenger and knocked unconscious.
He was treated in hospital for concussion, but was discharged on Sunday.
The incident occurred at 11.44pm at the intersection of North Road and Allen Street, in North East Valley.
A man, 21, gave himself up to police at 8pm on Sunday. He is charged with injuring with intent to injure.
Police in Dunedin say there are not always enough staff available for officers to work in pairs.
Inspector Dave Campbell says working alone on patrol is a fact of life.