A large vegetation fire at West Melton was likely sparked by the army, the Defence Force says.
A Defence Force spokesman confirmed it was likely the fire was caused by activity in the army's rifle range.
However, the exact cause of the fire would not be determined until a full investigation had taken place, he said.
Residents evacuated to escape the path of the fire have been allowed to return home tonight, but some roads will stay closed.
Five properties and the West Melton aerodrome were evacuated this afternoon after the fire burned out of control.
A police spokesman said cordons along Old West Coast Rd had been removed since the fire had been contained.
"People can start moving in ... unless they're on Weedons Ross Rd (north of Old West Coast Rd)."
Weedons Ross Rd, west of the army rifle range, will remain closed overnight, the spokesman said, along with a Waimakariri River-side track connecting it to Macleans Island Rd and Range Rd - the accessway to the firing range.
Firefighters were alerted to the blaze just after noon today.
Sixty firefighters, 40 police officers and six helicopters were involved in the response.
There have been no reports of damage to houses or buildings.
Residents were evacuated from their homes and a New Zealand Defence Force employee was injured in the fire, an army spokesman said.
The employee is not in a critical condition.
The fire covered an area of about a kilometre by 500 metres.
Police evacuated the aero club and an IHC residential property in Weedons Ross Rd, along with several houses in the vicinity.
Fuel tanks were removed from the aerodrome as a precautionary measure.
A welfare and reconciliation centre has been established at the West Melton Community Centre.
Halswell resident Andy Wilkinson, who lives by the quarry, said earlier the fresh blaze seemed worse than the recent Prebbleton fire, and his house smelt like a bonfire.
"Even with the Shands Rd one you couldn't really smell it. The wind is probably blowing the smoke towards us."
He said he smelt the smoke about 12.30pm and saw a huge plume of smoke when he looked out the window.
West Melton resident Amy Grant said the fire was about 2.5km from her house.
Police have advised her she should prepare to leave her home.
"I have been watching all the fire trucks coming in from town and helicopters flying around the area with monsoon buckets," she said.
"It's a rather scary thing since this is the third time now there has been a fire down Thompsons Rd way in the last two to three weeks."
Megan Grant, who was in Old West Coast Rd, said it looked like the fire was "travelling down the pines".
In Halswell, Antonia Hides said a "massive cloud of smoke" was rising above the houses.
"It looks much bigger than last week's [fire]," she said.
Smoke from the fire is visible from the central city.
Scrub fires have kept firefighters busy in the area in recent weeks.
Two weeks ago, a devastating fire near Prebbleton destroyed four properties, including two homes.
About 30 properties were affected in total as the blaze swept across 150 hectares.
- © Fairfax NZ News
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