A second helicopter is on standby to help with the blaze, which was first reported around the Courtenay Rd area at 5.47am.
An “unknown number of crew members” are fighting the fire, says Fire and Emergency southern shift manager Darryl Ball.
His message to locals was simple - “Please don’t go down and have a look.”
Just days ago firefighters were battling scrub fires that sparked along rail lines in Kirwee.
Multiple homes were threatened by the fires which were started by sparks from the brakes of a freight train.
The Canterbury region has been dealing with extreme temperatures, with 32C and windy conditions forecast today in Christchurch.