A Tongan boxer who was prevented from competing at the Commonwealth Games after being charged with a serious assault has been convicted of the crime which ended his sporting dream.

Sitaleki Maka was yesterday found guilty of assault and injuring with intent following an attack on a group of teenagers at the Lynfield skateboard park in February.

When the charges were laid against him in March, police applied for the 20-year-old lightweight boxer to be remanded in custody.

However, Judge Michael Behrens granted Maka bail so that he could represent Tonga at the Commonwealth Games in Melbourne.

Upon learning of the charges, Australian authorities denied Maka access to the country.

Yesterday, during a defended hearing in the Auckland District Court, Judge Josephine Bouchier heard how Maka had spent the day of the assault at training.

Afterwards he was picked up by friends and they went to the park to meet Maka's girlfriend and her friends.

At about 10pm, 18-year-old Robbie Halliday and several of his friends also went to the park.

Upon their arrival a 16-year-old, who cannot be named due to his age, was punched in the face by one of Maka's friends and fell to the ground.

"The next thing there was a Pacific Islander right in my face and he started to attack me," said Mr Halliday.

"I tried to defend myself. I heard a smashing bottle sound and fell to the ground. I just remember being on the ground and blood coming from my forehead."

Some of witnesses to the attack told of how Mr Halliday was also kicked while he was lying on the ground.

Maka denied attacking the teens, saying he was sitting in a car - tired from his training earlier in the day - while his mates fought.

His friend Lapilani Tevi also gave evidence to that affect but Judge Bouchier said she did not believe their version of events.

She found Maka guilty of hitting Mr Halliday on the head twice with the bottle and swinging it at the 16-year-old after he had been punched.

Tevi was convicted for his role in the attack last week and has been sentenced to one year's supervision and 300 hours' community work.

Maka is to be sentenced in October. He has been remanded in custody, pending a bail hearing today or tomorrow.

Outside the court the mother of one of the victims said she and the other parents were pleased with Maka's conviction.

"It's a shame that children in their own area can't go to a local place and hang out with friends."

She said being prevented from attending the Commonwealth Games was only the start of Maka's punishment for the injuries he had inflicted on the boys - two of whom had to be hospitalised. She hoped Maka would now be permanently banned from participating in his sport.

It is understood Maka has been registered with Boxing New Zealand and competing in events.

But the chairman of the Boxing NZ executive board, Keith Walker, said Maka's registration would be reviewed once a full report was available.

Mr Walker said people with serious convictions were usually deregistered, preventing them from representing the country or competing in amateur competitions.