A massive scrub fire is still raging out-of-control in Ngaruawahia, in the Waikato.

Fourteen fire crews are at the scene on Hakarimata Road, and a third helicopter has been called in to tackle the blaze.

Two helicopters and 11 fire crews are battling the blaze on Hakarimata Road, in Ngaruawahia.

Fire Service northern shift manager Colin Underdown says crews were first called to the blaze just before 5pm.

He says the fire is close to houses, but so far none are being threatened by the flames.