Locals in the vicinity of the Marsden Point oil refinery in Northland had a spectacular show tonight as the facility flared off gases.
A huge fireball was seen at the plant, 30km southeast of Whangārei.
A refinery spokesman said at about 10pm the refinery had an issue during the restart of the hydrocracker unit and as a safety precaution shut the unit down.
"Residents in the area will have seen a flare at the refinery.
"The flaring is a safety precaution to allow the safe venting of refinery gases during the shutdown of this unit.