A 14-year-old suffered a potentially fatal blood clot in his brain after he was attacked by school bullies in what appears to be a racially motivated attack.

The teen, Japanese-born Ryotaro Wright, needed emergency brain surgery in Waikato Hospital after the attack at Forest View High School in Tokoroa this week. Doctors say he was close to death.

Four students have been suspended and police are investigating.

Ryotaro's father Llewellyn said yesterday his son had been racially abused by four students over the past few weeks, including being called "whale muncher".

"I think they just think Asians are physically smaller than average Kiwis so it makes them easy targets. He's the type of boy who doesn't react normally, he sort of brushes things off."

On Tuesday morning, however, Wright believed his son was defending a friend.

"This big guy turned around and picked up Ryotaro and dropped him. I was told that these boys have been trying to bait Ryotaro for a while."

Ryotaro was dropped on his head during an interval break. Vomiting and concussed, he was taken to the school sick bay and an ambulance was called.

"We went to Tokoroa hospital and I want to thank the head nurse because she saw all the signs," said Wright. "She said 'We need to get the chopper ready, he is the priority'."

The nurse told Wright there was "something seriously wrong". "She had done tests on his eyes and his pupils were dilated; his eyes were not responding."

Ryotaro was rushed into theatre at Waikato Hospital. "We were told there was a massive clot. It was clotting so much it was pushing his brain to one side - that's why his eyes were dilating."

Surgeons opened the side of his head to relieve pressure - his face is now heavily swollen and bruised. He was discharged from hospital on Friday and faces a long recovery but still wants to return to Forest View.

School principal Richard Crawford told the Waikato Times the incident was "totally unacceptable".

He said the school's anti-bullying programmes had clearly failed on this occasion.

Wright wants his son's attackers charged, and the main protagonist expelled.