A woman has died after being injured at a party in Dunedin, in what's believed to be a structural collapse

Police and St John Ambulance were called to the Dundas Street property just before midnight after the occupants asked for help shutting down a party.

But when they arrived, a large number of people were already leaving and some were injured.

In addition to the death, two other people sustained serious injuries.

Otago Coastal Area Commander Marty Gray says anyone at the party who hasn't spoken to police should get in touch to help them piece together what happened.

Victim Support has been made available for those who were present.