A fire at a Wellington storage facility which burned for about 24 hours was arson, police say.
The blaze at Kiwi Self Storage in the suburb of Kilbirnie was started by an explosion, and fire safety inspectors say it is likely an accelerant was involved.
Detective Senior Sergeant Grant Ferguson told reporters outside the site on Wednesday police are now looking for a disguised man wearing a black hoodie and white cap caught by security cameras arriving at the building where the fire started.
"Some CCTV footage that has been viewed shows a male person arriving at these premises in the early hours that morning with what appears to be a large canister of petrol with them. They enter the premises and that is when the fire occurs."
Mr Ferguson said the did not force his way through the security gate and the camera did not catch the fire being started.
Police have spoken to the man whose unit the fire started in and believed this unit was targeted.
Almost 400 people are trying to get into their units at the facility to assess the extent of the damage.
The blaze burned for over 24 hours and at its peak 18 crews were on site. Temperatures in the building topped 1000 degrees Celsius and a digger was brought in to pull down the side of a wall to allow crews direct access to the flames.
The top floor of one of the the complex's five buildings was destroyed, while and the lower floor escaped with smoke and water damage. Precious items including Oscar and Bafta awards, family heirlooms and documents were destroyed.