A man has admitted his part in a road rage attack in Hamilton which left another man seriously injured.

Te Aho-o-Te Rangi Whara-whara, 22, was one of four young men charged over an incident which left Martin Kay with a fractured eye socket, broken finger and severe bruising as he was beaten in front of his family on November 27.

In Hamilton District Court this week he admitted charges of injury with intent to injure and careless driving and was remanded on bail to be sentenced in March.

The court was told how Mr Kay, his wife, their 16-year-old daughter and 14-year-old autistic son had been heading home when a car overtook them and a bottle was thrown at the family's car, the Waikato Times reported.

Mr Kay turned down a side street but the other car followed, ramming the back of their vehicle until a second car joined the chase, boxing the Kays in.

Mr Kay pulled into a driveway and honked his horn for help but was attacked by four men brandishing crowbars and hammers, one of whom began punching him in the face.

Mr Kay later told the Waikato Times he had grabbed the man, attempting to hold him until police arrived, but another man hit his hand with a hammer, breaking his finger.

Whara-whara had told police the attack came after Mr Kay crashed into his car.

A second man charged over the attack is due to appear in court next week.