Residents who were evacuated overnight when fire broke out on Christchurch's Port Hills have now been allowed to return home.
One of the helicopters that has been on the scene since first light. Photo: RNZ / Conan Young
People living in around 40 properties on Avoca Valley Road and Port Hills Road were forced to leave when the blaze broke out at late last night.
At the height of the fire 15 appliances and 60 firefighters - a mix of fulltime and volunteers crews - were deployed.
Area Commander for Fire and Emergency Dave Stackhouse said firefighters have been flat out from 5.45am this morning, trying to contain the blaze.
One resident has blamed young people using fireworks for starting the blaze.
Stackhouse said fire investigators were working with police and had identified some "good positive leads" and some "areas of interest."
"Our fire investigators eliminate all ignition sources, so fireworks is naturally one of them, but there are other sources we have to eliminate, that's how we come up with our cause and origin."
Area Commander for Fire and Emergency Dave Stackhouse speaks to reporters. Photo: RNZ / Conan Young
Fire and Emergency put out four fires in the area early on Wednesday morning. The fires were considered suspicious at the time, due to witnesses seeing people leaving the scene.
He said the loud bangs that some people heard about the time the fire broke out at around 11pm last night were from two LPG cylinders that exploded in a shed /studio that was the only structure that was destroyed in the blaze.
He said the fire has burned through around 25 to 30 hectares and has been difficult to battle because of the rough terrain - a mix of steep gullies, heavy vegetation of pine trees, gorse, thick scrub and grasslands.
"It's been a really good job and we've managed to protect all the structures along the Port Hills Road and the Avoca Valley. So I'm really happy - it's been a good effort."
A couple of southwest changes during the night increased the intensity but the winds eased up about 4am.
Area Commander Stackhouse expects they will maintain a presence at the scene over the next day or so.
The scrub fire has destroyed around 25 to 30 hectares of scrubland and pine trees, he said.
Resident's anxious night
One owner spent a nervous night watching the flames get closer to his home.
Kester Vos said he noticed the flames at around 11pm.
"Within a pretty short time afterwards the police were on the doorstep saying 'you've got two minutes, grab what you can and get out'. The first thing to do was get all the cars off the property and the dogs.
"Then it was pretty much, OK, we had to clear out of the area, so I've been standing here since 11 o'clock last night."
Vos said the fire was started by young people letting off fireworks.
Kester Vos says young people letting off fireworks may have caused the blaze. Photo: RNZ / Conan Young
At first light two helicopters carried out an aerial survey of the fire.
Firefighters at the scene near where the fire began on Port Hills Rd in Christchurch. Photo: RNZ / Conan Young
Earlier today Area Commander Stackhouse said the flyover looked positive: "Our crews did a fantastic job stopping the fire from spreading up the hills and potentially impacting homes.
"Our priority this morning is to keep it within the area we have currently contained it to.
"The weather is on our side, with only light winds forecast, this should help us in our work throughout today," he said.
The scene last night. Photo: Twitter / @omantramusic
The fire started in the area of Alderson Avenue, off the Port Hills Road close to the suburb of Hillsborough.
It was on the side of the hills facing the city, so Christchurch residents could see it and were phoning Fire and Emergency.
State Highway 76 has been shut off at Curries Road and motorists are being directed away from the area.
Photo: Facebook / Chris Lynch
One of New Zealand's most devastating fires spread across the Port Hills in 2017, killing a helicopter pilot, burning through 1600 hectares of land, gutting 11 homes and damaging more.
Witnesses were in court in August as Insurer IAG, lines company Orion and Christchurch Adventure Park debated who should pay for the damage.
The 2017 fires began in two separate locations several kilometres apart but merged, and prompted a review of the fire services in New Zealand, culminating in the formation of a national fire service - Fire and Emergency.
Efforts were made in the wake of those fires to plant 10 million trees in the area to reforest it.