Christchurch residents who lost their homes in the Port Hills fire in February are considering legal action, after new video footage was released appearing to show a burning chairlift contributing to the blaze spreading.
The video shows the Christchurch Adventure Park chairlifts running as the fire rages nearby, before a new blaze breaks out and quickly spreads beneath the chairlift lines.
The resulting fires are thought to have gone on to destroy several homes in Worsleys Rd.
The footage emerged as police confirmed they had begun a criminal investigation into the fires, one of which they say was deliberately lit.
There were two separate fires which started on February 13, police said. The two fires later merged into one massive wildfire on February 15.
Fire and Emergency New Zealand has been undertaking two investigations, looking into the cause and origin of how the two separate fires started.
The cause and origin of the Marley's Hill fire was still being finalised but police said it was suspicious. Anyone with new information is being asked to contact police.
Detective Inspector Greg Murton said the fire service's report or its findings cannot be discussed as it is now a criminal investigation.
"We understand this may be frustrating for residents who are anxious to know more information about the fires."
The investigation into the cause and origin of the second fire is still a couple of months away.
Kieran Grace, one of the Worsleys Rd homeowners, said he and other families had struggled to get any information from fire authorities on when or how their homes were destroyed.
"Today however we are absolutely appalled at videos showing the Christchurch Adventure Park chair lift starting new fires near our property boundary," he said.
"The videos show the chairs catching alight from the Marleys Hill fire and starting new fires below the haul line."
The park left the chair lift running to limit damage to the main line, but the video appears to show the chairs starting "multiple new fires" which ultimately spread to their houses, Grace said.
"It appears at no point the fire authorities, Christchurch City Council or The Adventure Park found it necessary to turn off the chair lift. As a result, seven homes were destroyed in the hours following the chairs catching fire."
Grace and several others are now seeking legal advice to recover the losses from property damaged by the fire.
A spokeswoman for the Christchurch Adventure Park, which runs the chairlift, told the Herald the cause of the fires was under investigation by fire authorities "and we await their findings".
"We have worked closely with the authorities throughout the fires and in the months subsequently."
She told Fairfax running the chairlift during a fire was "standard operating procedure as failure of the haul rope would be catastrophic putting lives at risk".
The Christchurch Adventure Park has been closed since February, but it is set to reopen for summer.
Residents who lost their homes asked the local fire authority - the Selwyn District Council - for information about the fire response and assessments and warning of fire hazards.
The council declined their request under local government official information laws, saying the release of the information would prejudice the investigation.
"An Operational Review is currently underway and we believe it is necessary to withhold this information to avoid potential prejudice to the Operational Review, with this review being a measure to protect the health and safety of members of the public," the council said.
Grace said the residents had also been made to sign a non-disclosure agreement by the NZ Urban Fire Service.