Wairoa police are seeking help from the public about what they say was an unprovoked attack on a 44-year-old man and his 16-year-old stepson.
Sergeant Aubrey Ormond says just after midnight on Saturday, the two were standing outside the Frasertown tavern west of the town, when a car pulled up beside them.
He says about six men got out of the car and attacked the man and the teenager, and knocked them both unconscious.
Mr Ormond says the two were then kicked and punched as they lay on the ground,.
He says a passerby intervened and the pair was taken to Wairoa Hospital and treated for head and facial injuries.
The police found a green Ford Falcon in a ditch near the tavern.