A car being torched is thought to have caused a blaze firefighters spent all night bringing under control at Pipiwai and which forced a family to flee their home.
The family of six spent Saturday night with friends after the fire on Moore Rd, Pipiwai, near Whangarei, quickly spread to a steep, scrub-covered hill and threatened their house.
It was among several suspicious scrub and grass fires on the weekend that stretched resources and put the lives of people and native wildlife in danger.
A fully protected green gecko suffered severe burns to its four feet in a scrub fire at a separate location in Pouto on Thursday last week.
The native reptile was handed to the Native Bird Recovery Centre in Whangarei on Friday.
An irate principal rural fire officer for Whangarei and Kaipara, Kevin Ihaka, pleaded for public help to identify those responsible for the spate of unnecessary fires.
Costs would be recouped from the people who caused fires, he said.
Whangarei Senior Sergeant Stephanie Hudson confirmed the fires on Moore Rd and three in Pouto, south of Dargaville, were being treated as arson. An investigation was under way.
Fire crews from Whangarei, Kamo, Maungakaramea, Hikurangi, Kamo, and rural fire parties battled the whole night to bring the Moore Rd fire under control.
Two hectares of scrub were burnt.
Mr Ihaka said the ferocity of the Moore Rd blaze meant he could not send a crew to another scrub fire that started about the same time at Pouto, burning 10ha.
"It's really frustrating that several fires are happening around Northland at the same time and they are stretching our resources. Not one [fire] needed to happen but they, sadly, are and are putting lives at risk," Mr Ihaka said.
"Don't light fires - it's too dry. We'd be very keen to hear of any suspicious activity and people should note things like vehicle numbers and forward them to police."
Mr Ihaka said a helicopter with a monsoon bucket, used to fight the Moore Rd fire which started about 8pm on Saturday, was the only one available after two local choppers were sent to a fire on Kawau Island.
Open fires are restricted in Whangarei and Kaipara. Mr Ihaka said no permits were being issued because of dry weather and a spate of scrub and grass fires.
Alex Wright, a resident of Wright Rd which is also off Pipiwai Rd, called 111 after seeing smoke and later flames in Moore Rd, about 2km away, on Saturday evening.
"Scrubby and overgrown grass meant the fire got hold pretty quickly up a steep hill.
Fortunately the winds died down but it still was a fairly intense fire and it was getting close to a house," she said.
Her farm worker, his partner, her grandmother and three children were evacuated from the house and slept at a friend's house on Moore Rd.
Mrs Wright said the worker had towed an abandoned car on Moore Rd to a nearby quarry on Saturday. The vehicle was found burnt out in the evening.