An Auckland apartment building under construction that has been a repeat target of arson has been temporarily closed, police say.
Police said all the fires started when flammable substances, such as fabric and paper, were put on stoves and then the elements turned on.
Apartments have been water damaged by sprinklers activated by smoke alarms.
Detective Senior Sergeant Nina Pedersen told Morning Report access to the site has been easy because so many contractors are at work.
"Site management have closed the site down for 48 hours so they can review their procedures and implement some new procedures to increase security and safety for their people."
She said anyone with information, including rumours and overheard conversations, should contact police.
The apartment building was due to open next month.