A man has died and two people have been treated in hospital after a wild brawl on the New South Wales far north coast.

A 46-year-old man, who was one of three people stabbed at Knox Park at Murwillumbah, has died after the midday incident on Tuesday.

An 18-year-old man was taken to Gold Coast University Hospital in a critical condition with wounds to his chest.

Another man, 29, was taken to the Murwillumbah Hospital with minor injuries and has been released.

Police have arrested a 32-year-old man who is assisting with enquiries.

Local woman Jade Juless was playing tennis nearby.

“There were about 30 or so teenagers and they just started fighting,” she said.

“One had a stick trying to hit other people, and then they started throwing glass at each other and we could hear it.

“That’s when I thought I would ring the police because it was right near the children’s play area.

“We could hear the glass smashing.

“You just didn’t know which way they were going to go, whether they were going to go into the skatepark or walk around or what.”

– ABC