Firefighters in the Far North are stepping up their efforts to contain a substantial blaze in rural bush.

Several crews are at Pipiwai Rd at Matawaia, south of Kaikohe, into their fourth day of trying to contain the flames.

Shift commander Daniel Nicholson says it's in a rural area, and crews have been working through the night.

He says it's burning through 60 to 100 hectares of bush.