A massive fire has burnt down a former psychiatric hospital in the south Auckland suburb of Kingseat.
Firefighters are dampening hotspots while investigators are working out how the blaze started in the historic building.
It was used for paintball, and was part of a large property that contains the Spookers haunted attraction.
Part-owner Alex Malikov says they're counting their blessings no one was injured but the cause is a mystery.
"It was only used as an arena so it would only be opened when we had paintball groups. It was not occupied and there was no power going to the building," he says.
Fifteen fire appliances and 60 firefighters battled the blaze that broke out around 4am.
The fire service said they're treating it as suspicious.
"We cannot gain access to the building and we're very concerned about structural collapse," assistant area commander Dave Woon told Newshub on Saturday morning.
"We have water limitations here and that's causing some anxiety with our firefighters.
"The present tactic at the moment is to surround it and work from the outside of the building with the little water we do have.
"Most of the fire is under control, but it's the central parts and upper parts that we're struggling with. We don't want out firefighters getting too close because structural collapse is imminent."