One person is dead after a helicopter crashed fighting fires in the Port Hills near Christchurch on Tuesday afternoon.
The Civil Aviation Authority says it understands the helicopter that crashed was a commercial operator.
The helicopter was part of a fire fighting effort battling two blazes on Marley Hill and Early Valley Rd.
Selwyn Principal Rural Fire Officer Douglas Marshall says the crash is an "absolute tragedy".
"Firefighting is difficult dangerous work, but no one ever anticipates this type of activity occurring, so our thoughts are with the family at this time," he says.
"We stood all the machines down and our pilots make their own call about whether they'd like to continue and a number have chosen to continue, which speaks to their decision making, and also what their companion would have probably wanted as well."
The first fire began in scrub and pine trees on Early Valley Rd late on Monday afternoon, before a second blaze started on the Summit Rd.
After monitoring the fires overnight, helicopters with monsoon buckets were seen taking to the skies from first light.
At least 100 firefighters and 18 appliances fought to keep the fire from spreading overnight - however the Early Valley Rd fire has now crossed Summit Rd and is heading towards Governors Bay.
Selwyn District Civil Defence say the fires have spread across more than 700 hectares of scrub and vegetation.
Christchurch Helicopters, where former All Blacks captain Richie McCaw works, says it wasn't one of their helicopters.
All flights fighting the fires have been grounded for the safety of other pilots.