Fire crews will today continue dampening down a large scrub fire which is smouldering north of Auckland.

A skeleton crew remained in place overnight monitoring the blaze near a commercial pine forest in Dome Valley, about 10km north of Warkworth.

Principal rural fire officer Bryan Cartelle said the fire had not grown beyond the 71 hectares it had spread to yesterday.

"It's smouldering, it's smoking, there are pockets of active burning but nothing of concern at this stage," he said.


"It's a big ground-based operation today so there's a lot of people heading out and ... we've got an aerial support operation and some heavy machinery operation so there are several different operations going on today."

The priority was been to get firebreaks in place to stop the fire from spreading any further.

"The burn period is the early afternoon so that's when things will test us."

Residents near the fire would be concerned by the smell of smoke but Mr Cartelle moved to reassure them.

"The fire is being held in the valleys at the moment."

The cause of the blaze was not yet known but northern fire communications spokesman Jaron Phillips said it may have been started by skeet shooters seen in the area.

On Saturday night a helicopter pilot fighting the fire needed medical treatment for ash in his eyes.

He was grounded so he could be treated by St John Ambulance officers.