"The temperature is already starting to climb so we're really keeping a close eye on it," he says.
"It's too early to say for certain what sparked the blaze, but we're looking into that."
He said it's important that people are aware of how dry the conditions are in Northland, and several other parts of the country.
"A fire can start pretty easily when it's so dry, so people need to pay attention to the conditions around them. They need to act in a safe way and be extra vigilant."
The fire raged through scrub in a reserve west of Whangarei and spread to around 130ha of bush since it broke out yesterday afternoon.
Eight crews from Whangarei and Kaikohe were called in to tackle the blaze.
Fire and Emergency said the blaze burned on two fronts. A 400m long fire front was left to burn out of control throughout the night.
Northern communications shift manager Paul Radden said fire crews with a bulldozer and digger, plus six helicopters gathered to fight the fire this morning.
No buildings were threatened.
Yesterday residents described seeing massive plumes of brown smoke billowing from the reserve.
Helicopters and ground crews protected buildings initially threatened by the raging fire.
