One of the Port Hills fires in Christchurch in February is suspicious, police say, and they're calling for new information in a criminal investigation.
The blazes started as two separate fires on February 13 and they merged into one large fire two days later.
A helicopter pilot died while fighting the fires.
Fire and Emergency New Zealand has been undertaking two investigations, looking into the cause and origin of how the two separate fires started.
While the investigation into the cause and origin of the Marley’s Hill fire is being finalised it can be confirmed that the cause of the fire is suspicious and requires police investigation.
"These fires had a devastating impact on the Port Hills and wider community and we encourage anyone who has information that may help find the person responsible to come forward," said Detective Inspector Greg Murton.
Mr Murton said as it is now a criminal investigation, the report and its findings cannot be released or discussed.
"We understand this may be frustrating for residents who are anxious to know more information about the fires," he added.
The investigation into the second fire is still ongoing and expected to take at least a couple of months, said Leigh Deuchars of Fire and Emergency New Zealand.