Firefighters from Ranfurly, Naseby, Blackstone and Dunstan volunteer fire brigades are assisting with the wildfires that broke out in the Waitaki district last night.

Firefighters supported by helicopters are working to put out the two fires in Waitaki, which began shortly after midnight.

Both fires are now contained, but work to consolidate the perimeters and extinguish hotspots is underway.

No dwellings were lost in either fire, but a small number of farm buildings have been destroyed, or damaged at Nenthorn.

That fire was mapped at 78 hectares of farmland during aerial reconnaissance.

Fire and Emergency Incident Controller Bobby Lamont said the Middlemarch crew, which was first on the scene at Nenthorn, did "an amazing job" to protect a house from the flames.

Crews from six other volunteer brigades responded, as well as the command unit from Dunedin.

Fresh crews supported by three helicopters are working at Nenthorn this morning.

A fire investigator will be examining the area where the fire started to establish the cause.

Bobby said that two other fires were started by embers blown by the wind from the original blaze.

The second fire, at Earthquakes near Duntroon, has burnt about 30 hectares of conservation land.

Incident Controller at that fire, Jason Sarich, said that firefighters had worked very hard in challenging conditions to contain the fire, with gale-force winds overnight.

Another 30 firefighters and two helicopters were working on the Earthquakes fire this morning. 

They are being joined by two crews of firefighters from the Department of Conservation today.

Fire and Emergency’s command unit from Timaru is also at the scene.