Firefighters have contained the perimeter of a large grass and scrub fire near Lake Benmore.
Incident controller Michael Harrison said crews were mindful of the need to fully extinguish hot spots tonight as winds were forecast to increase in the area at the end of the week.
"Crews will also be back in the morning to continue this important work to prevent this fire flaring up again when the fire danger increases," he said.
The 5ha fire started in stubble late this afternoon, burnt through paddocks and then moved up a hill into scrub.
Volunteer firefighters from Twizel, Omarama, Otematata and Lake Tekapo all responded to the fire, supported by three helicopters.
No homes or structures are reported to have been damaged.
Mr Harrison said initial reports suggested that the fire had been sparked by farm machinery but there would be further discussions with the landowner to confirm the circumstances.
He asked all farmers and contractors in the area to be aware of the high fire danger because routine activities could cause a spark that would easily set the grass on fire.
"The fire danger will only increase as it gets windier as predicted," he said.
If machinery work could not be deferred then it was best to carry out operations in the early morning, when the temperature is lower and the humidity was higher.
The whole of the Mackenzie Basin, including the Upper Waitaki area where the fire started, is in a prohibited fire season, which means there is a complete ban on outdoor fires.
Temperatures in the area rose to 28degC with strong northwesterly winds earlier in the day before cooling later in the afternoon to about 20degC.