The organiser of a community festival in Porirua is disgusted that witnesses to a brawl filmed it instead of breaking it up.

Footage has emerged on social media showing a girl being punched to the ground and repeatedly kicked in the head.

The attack happened at Creekfest in Cannons Creek on Saturday.

Police are investigating.

Event organiser and Porirua Whanau Centre Trust chief executive Liz Kelly said she was comfortable with how officials at the event dealt with the brawl.

But she said the fight could have been stopped if those people filming intervened.

"I'm disappointed that we have people in our society who have that sort of mentality that rather than helping somebody that they would think that it's more important to film it."

READ MORE: Porirua mayor calls attack on girl 'horrific'

Kelly said the attack was the first in the 12 years she had managed the event.

She said what happened was really sad.

"My heart goes out to the victim and to her whanau but the actual incident had nothing to do with Creekfest.

"I've been told that this is a grievance between two families and they brought their grievance to Creekfest."

Porirua mayor Mike Tana said the brawl happened as people were leaving the festival.

"It was out in the car parking space off to the side of the event.

"It did seem they were a group of young kids that knew each other and obviously something had happened and they were having an altercation that just didn't need to happen."

He said it was horrible.

"If it was my daughter who got involved or got hurt I'd be devastated."

About 32,000 people attended Saturday's festival.

Creekfest started in 2004 to raise awareness of programmes and services available in the region to achieve better health and well-being outcomes.

Tana said overall the day had a family atmosphere and spirit about it.

"This is an event that one incident like this should not mar and should not stop."