Matthew Gale, from Gerringong, was knocked unconscious and had his nose broken after he was king-hit by a mob during the violence which erupted in Kiama on Monday afternoon.

Fighting also occurred in Wollongong, Thirroul and Shellharbour, as drunken teenagers used the day as an excuse to riot.

The 17-year-old cannot remember anything of the attack but his furious father, Adam Gale, has pieced together details from witnesses.

He said Matthew was apparently pounced on by a group of youths whilst sitting with two female friends outside Kiama surf club.

"They blind-sided him," Mr Gale said. "The guys just walked up and hit him. The first punch is probably the one that knocked him out because he has no recollection of being hit."

When Matthew regained consciousness, his friends helped him over to two police officers - but were shocked when the officers turned their backs and looked the other way.

"He was helped over to the police because his legs weren't working very well at the time," Mr Gale said. "He was concussed and his nose was broken. He was in a pretty bad way.

"I want someone to explain to my son why, when his old man's always taught him that if he's in trouble he should find someone in a uniform, when he takes that advice it turns out to be useless.

"I'd like an explanation and an apology for him."

After being ignored by police, Matthew's friends took him to paramedics, who cleaned him up and advised him to go home. He passed out three times that night and paramedics were called out to treat him at home for low blood pressure.

Matthew missed his first day back at Kiama High School yesterday while he recovered from his ordeal.

When asked about the incident, Lake Illawarra police Inspector Steve Johnson said: "If he's not happy with the police response then he should speak to us about it."