Up to 20 homes and structures have been destroyed in the village of Rappville, south of Casino, as a bushfire emergency grips northern NSW.

The NSW Rural Fire Service (RFS) downgraded emergency warnings for two separate blazes, which are burning within about 70km of each other in the state's north, to watch and act overnight.

The fires are at Busbys Flat and Drake had nearly 1,000 firefighters working them through the night.

Latest fire advice: Busbys Flat: Watch and act. Residents in Coombell, Ellangowan, Rappville, Wyan, Wineshanty, The Island, Myrtle Creek, West Bungawalbin, Busby Flat or Mount Belmore State Forest should continue to remain vigilant and be ready to act if fire should threaten properties. People to the east of Summerland Way in the area of Myall Creek Road, Duke Road, Neileys Lagoon Road and Bungawalbin Creek are advised to be alert for embers and spot fires.

Busbys Flat: Watch and act. Residents in Coombell, Ellangowan, Rappville, Wyan, Wineshanty, The Island, Myrtle Creek, West Bungawalbin, Busby Flat or Mount Belmore State Forest should continue to remain vigilant and be ready to act if fire should threaten properties. People to the east of Summerland Way in the area of Myall Creek Road, Duke Road, Neileys Lagoon Road and Bungawalbin Creek are advised to be alert for embers and spot fires. Drake: Watch and act. People in the areas of Ewingar, Broadwater Flat, Keybarbin State Forest and the Mount Belmore State Forest should continue to monitor conditions closely.

The RFS confirmed several homes had been affected by the "very dangerous" fire that was "spreading quickly" around Rappville, near Busbys Flat.

Rappville resident Danny Smith said: "I've lost the bloody sheds, the house, lost everything."

"We might have saved the second place but everything else has gone."

On Tuesday evening, about 50 people sheltered at the public school in Rappville, which was saved.

RFS Deputy Commissioner Rob Rogers said several houses in Rappville had been destroyed but authorities did not yet have a count of property losses from all the fires.

"Rappville is the centre of attention because we know a number of homes have been burnt and a number of residents have been significantly affected by that fire and continue to be isolated by downed power lines and obviously no water in the area," he said.

"So we're doing our best to get some help to those people, but it's going to be an extremely long night for a lot of people, along with firefighters."

This house in Rappville was gutted by the fire. ( ABC News: Matt Coble )

He said conditions were expected to ease overnight but firefighters would still have to counter significant threats from "hundreds of kilometres of fire line".

Meanwhile, the fire at Drake has already burnt more than 70,000 hectares of land over the past few weeks.

The fire has now crossed the Clarence River and is burning in an easterly direction through the Keybarbin State Forest and Mount Belmore State Forest.

Firefighters endured very difficult conditions on Tuesday, with temperatures of up to 40 degrees Celsius in northern NSW.

Sheep graze near Tenterfield's cemetery, which is right next to the fireground. ( ABC News: Catherine Marciniak )

Earlier in the day, the RFS issued emergency warnings for fires at Tenterfield and Jackadgery, but they were downgraded shortly before 8pm.

Tenterfield resident Phillip Krauss said he feared there would be worse to come for the town this bushfire season.

"I honestly think if this drought doesn't break, it's going to be a very bad summer," he said.

Peter Reid said the past month had been "horrendous" for people in the town.

"This would be the fifth major fire we've had in the district," Mr Reid said.