Six helicopters are being used to fight a burn-off on farmland that got out of control about 10km from Te Anau in Southland.
Fire and Emergency NZ was alerted to the fire in the Mt Prospect area about 2.30pm on Friday, says spokeswoman Sally Chesterfield.
The fire initially covered about 300 to 400ha but has spread to more than 1000ha.
Chesterfield said the fire isn't threatening any buildings as it is located in a very unpopulated area, a long way from any buildings or sheds.