Fire crews are into their third day of fighting a bush fire on the Karikari Peninsula in the Far North.

The blaze began on New Year's Eve, near the DOC campground at Matai Bay. Helicopters with monsoon buckets and multiple ground crews have been fighting it since.

Northland deputy principal rural fire officer Lance Johnston said while it's under control, it's not contained or out. He's warning holiday-makers to be alert.

"There's a lot of people living or holidaying out on that peninsula and a lot of coastal areas at the moment, and these fires don't stop for anybody when they get going, so everyone's got to be careful," he said.

A flare-up yesterday afternoon forced emergency services to close the main road, because of the traffic in the area.

Crews have been working to dampen hotspots through the 10-hectare area, and high winds aren't making it easy.

Johnston is asking people be careful in the area - and observe the fact there's a fire ban in place.

"It's a prohibited fire season out on that peninsula anyhow, and people should not be having open fires and that means use of fireworks- we believe this possibly could have started from fireworks."