A clothing brand giveaway has descended into chaos with people run over by trail bikes and the riot squad pepper-spraying crowds at a NSW skate park.

Police now combing through footage of the wild scenes, warning attendees they could be arrested.

T-shirt giveaway descends into chaos with riot squad called 9News

Hundreds headed to Mayfield in Newcastle for the PR stunt by streetwear brand Bad Apples yesterday afternoon.

The company posted online it was giving away “300 free tees, 450 other items” and “at least $5000 cash to people who come and show us what you’ve got”.

Hundreds on foot and dozens on trail bikes took over the roads and tore up the grass, mowing down anyone in their way.

Superintendent Kylie Endemi from NSW Police called the behaviour “nothing short of dangerous”.

T-shirt giveaway descends into chaos with riot squad called 9News

The riot squad moved in, using pepper spray to break up crowds.

One woman was arrested but released following further inquiries, and investigations continue.

“We have excellent footage obtained through body-worn video, through in-car video through Polair that was in the sky,” Endemi said.

“We will identify those who chose to behave in such a deplorable way.”

The clothing brand was not shying away from the violence, instead posting footage on social media.

“The police forward commander tried to engage with the event organiser yesterday in terms of helping us to restore order,” Endemi said.

“They did not assistant police in that regard.”