Firefighters have been battling a blaze in Central Otago which started on Saturday morning and has burnt through nearly 2800 hectares of tussock and scrub.
Hot conditions and winds of up to 50km per hour caused the blaze, which started near Te Papanui Conservation Park in central Otago, to spread on to land owned by the Dunedin City Council.
Up 10 helicopters at a time have been in the air today, and four ground crews who were ferried in by helicopter joined the attack where conditions allowed.
Firefighting activity continued until nightfall and will resume at first light, an update from Fire and Emergency said. The fire is in a remote area with no road access, so while it's being monitored overnight there will be no fire suppression during darkness, it said.
One home has been evacuated as a precaution and strong winds and dry conditions are forecast to last until the early hours of Sunday morning.
The cause of the fire has not yet been confirmed.
Earlier in the day smoke from the fire was visible over a large area of South Otago. People who are sensitive to smoke are being advised to stay indoors with windows and doors shut, and to turn off air conditioning.
The 21,000ha park is managed by the Department of Conservation as a "remote experience area" and was opened in 2003.
A DOC spokesperson today declined to comment on the fire, saying DOC will comment on Monday.
The area open to the public is popular for walking, mountain biking, horse trekking, cross-country skiing and hunting.
Te Papanui provides a home for a huge variety of native plants and animals, including 547 species of native insects, as well as the narrow-leaved snow tussock and many rare wetland plants.
The park also fulfils a significant role to the people of Otago region, protecting 60 percent of Dunedin's water catchment area.
Meanwhile, earlier today firefighters were dampening down hot spots of a fire which continued overnight at Bucklands Crossing in Mountain Rd, near Waikouaiti.
The blaze covers an estimated 16 hectares of felled pines.