Three children aged five, eight and nine have been referred to Youth Aid for setting a large scrub fire in Gisborne.
Police believe the children - all locals - were playing with a cigarette lighter.
Two houses were evacuated and several others were threatened by the fire which started in grass in a reserve in Cambridge Terrace about 2pm on Friday.
The fire spread rapidly towards houses on the eastern side of the reserve, then burned over the corner of Kaiti Hill towards Endcliffe Road.
It took firefighters and two helicopters more than an hour to get the fire under control.
The flames came to within 10 metres of some property boundaries, but there were no reports of injuries or property damage.
The children appeared to be unsupervised, with no adults in the area.
- Additional reporting Gisborne Herald