A fire at an abandoned freezing works in Penrose, Auckland, which destroyed several buildings has been officially declared as arson.
The Fire Service says the blaze is now out and firefighters have left the scene.
The building had been due to be demolished following a large fire in 2008, but it went up in flames again just after 8pm on Friday.
A Fire Service investigator, Ray Coleman says he has now handed the case over to Police following confirmation that the cause of fire is the work of an arsonist.
Southpark, the company that owns the old Southdown freezing works site, says it had been due to finalise the tender for demolition of the building this week.
Property and utilities manager Peter Sanders estimates the $2 million cost of demolition could now fluctuate by up to 10%.