Fire and Emergency New Zealand (Fenz) said the fires - at Nenthorn, about 30km from Middlemarch, and in the Earthquakes area about 7km from Duntroon - were reported shortly after midnight today.
Residents of three properties near the Nenthorn blaze self-evacuated overnight and but were not yet able to return to their homes, Fenz incident controller Bobby Lamont said in an update about 5pm today.
The 78ha Nenthorn fire has destroyed or damaged farm buildings. In gale-force winds, flames came close to a farmhouse, but crews were able to save it.
Mr Lamont said the Middlemarch crew, which was first on the scene at Nenthorn, did "an amazing job" to protect a house from the flames.
"One came very, very close to being extremely damaged so they've done a really, really good job."
Crews from six other volunteer brigades also responded, as well as the command unit from Dunedin.
Mr Lamont said tonight crews with hand tools, supported by excavators and helicopters, were digging out and extinguishing deep-seated fires under two large stands of trees throughout the day.
"One crew will monitor the fire overnight and there’ll be fresh crews arriving in the morning."
A fire investigator would be trying to determine the cause of the blaze.
Incident controller Jason Sarich said crews had worked very hard in challenging conditions, which included gale-force winds overnight.
He said tonight that most of the fire was in grass, which spread rapidly.
"The wind dropped around 7am this morning and crews were able to get on top of it pretty quickly."
The fire has burnt about 30ha of conservation land.
Mr Sarich says the fire is completely contained and Doc fire crews were now working with helicopters to mop up hot spots.
Crews will patrol and monitor the fireground for the next few days.
About 30 firefighters, two helicopters and a Fenz command unit from Timaru were at the scene this morning.
