The Kaimaumau blaze in Northland, which has burned for nearly two weeks, is now 65 percent contained.
Fire and Emergency spokesperson John Sutton says ground crews are being supported by helicopters today to establish and strengthen containment lines.
Sutton said today's conditions were not as favourable as earlier in the week, with wind gusts of up to 50 kilometres per hour forecast alongside a humidity drop.
He said flare-ups may occur in these conditions and extra aircraft have been placed on standby.
Additional crews will arrive tomorrow as volunteers become available after their holidays.