The Waipoua River Fire, which burned through 100ha of scrub and pine, was caused by an out-of-control rubbish fire.
Fire and Emergency New Zealand revealed the cause today.
Residents were evacuated last week after the fire came within metres of homes within the settlement.
At its height around 100 firefighters and eight helicopters battled the blaze.
Parts of the region have entered a prohibited fire season on the West Coast and upper Far North areas due to tinder-dry conditions.