A brawl has broken out at the Auckland waterfront drawing police to the scene in a flurry of sirens.

A bystander who was standing at the Auckland Ferry Terminal said he had heard an alarm go off to evacuate a nearby building.

About 200 people spilled out onto the pavement, he said.

"Everyone was running away and saying 'run'!"

The man said he thought he had heard a gunshot amongst the chaos.

A police spokesperson has said no guns were fired at the incident.

It was understood at least one person has been badly injured and another person has moderate injuries.

The fight broke out about 9.30pm.

An ambulance is at the scene.