Watch: Businesses threatened by suspicious fire at Ruakaka

A crew of more than 20 firefighters battled a suspicious blaze at Ruakaka this afternoon.

Five fire appliances and up to 25 staff, with a helicopter on stand by, were called to a grass fire just before 1pm which started in an open park-like area on Sime Rd.

The fire quickly spread to nearby gorse and pampas scrub and crossed the road engulfing a 2000 square metre area and threatening two nearby businesses.

Ruakaka Chief Fire Officer Darrell Trigg said this added "an element of urgency" to the situation. Crews brought the blaze under control within an hour and remained in the area for several more, dampening down and investigating the scene.

Mr Trigg said the blaze was being treated as suspicious.

Revitaglass and North Sawn Lumber were the businesses at risk from the blaze.

"The glassblower was certainly potentially in danger of the fire jumping into their property but we managed to cut that off," Mr Trigg said. "And with the saw mill, the fire was close to some of their timber stacks so there was an element of urgency about containing it."

Mr Trigg said North Sawn Lumber lent diggers and loaders used to help contain the fire.