Half a dozen Wellington fire brigades worked through the night to extinguish a suspicious fire near Transmission Gully in Whitby.
Firefighters were called to the blaze - in a culvert on Waitangirua Link Road - at 12.30am on Tuesday.
Fire and Emergency shift manager Murray Dunbar said water was scarce in the area, so crews from Wellington and a water tanker from Remutaka were called in to help.
Dunbar said the fire had been deemed suspicious, and police had been notified.