Riot police have responded after hundreds of teenagers swarmed a Woolworths supermarket in Melbourne and violence erupted on a beach.

Footage shows an estimated 200 young people streaming into Woolworths and running amok at Mordialloc, a coastal suburb, about 3.15pm on Wednesday.

They were reportedly smashing items, pulling products off shelves and causing general mayhem as they overtook the aisles.

Most of the teens pictured appeared to be shirtless and barefoot.

In one video, laughter can be heard as the invaders grab armloads of supermarket items and wander the store.

Riot police respond to reports of teens running amok in Mordialloc. Photo: Nine News

After leaving Woolworths, the crowd reportedly regrouped at the beach near Mordialloc pier, where further footage shows violence taking place.

In one video doing the rounds, a young woman in swimwear is kicked as she lies on the sand trying to protect herself.

A swarm of riot police carrying pepper spray responded to the incidents and officers were seen apprehending individuals at the beach.

One teen was reportedly arrested at the scene and remains in custody.