About 50 firefighters from 14 crews managed to bring "a fair portion" of the out-of-control burn-off under control by 5.30pm, Kurow Volunteer Fire Brigade chief fire officer John Sturgeon said.
The fire steadily swept through "very dry" matagouri, scrub and grass in a northwesterly wind, and by late afternoon the roadside at Meyers Pass Rd about 25km northeast of Kurow was left charred and smouldering.
A large plume of smoke was visible from the South Canterbury command unit where operations were based and helicopters with monsoon buckets worked further down the road.
But rural crews from Waimate and Cattle Creek would remain at the scene as the other fire brigades were released as night fell.
A Fire and Emergency New Zealand spokesman said crews from Timaru, Waimate, Cave, Kurow, Otematata, Waihaorunga and Glenavy were at the scene.
No structures were threatened by the fire in the Meyers Pass area, which linked the Hakataramea Valley and Waimate, he said.
The farmer called emergency services after the burn-off got out of control about 2.40pm.
Only helicopter mapping after the fire could confirm its size, but he believed at least two high-country properties had been affected, Mr Sturgeon said.
