Conditions eased slightly overnight thanks to a southerly change and the fire danger alert was downgraded from emergency to watch and act.

In the early hours of the morning, firefighters were working to set containment lines and protect properties as they slowed the spread of the fire.

Last night was an extremely tense one for residents of Braidwood, who had been told it was too late to leave and advised to take shelter as fire crews battled the North Black Range fire.

READ MORE: Firefighters brace for deteriorating conditions on Saturday

The fire was moving in an easterly direction on Friday afternoon but the change in conditions means the fire is moving in a more northerly direction on Saturday morning.

The fire in Tallaganda National Park, which was started by lightning on Tuesday, covered more than 19,000 hectares on the latest RFS estimate at 2am.

People in the areas of Bombay, Little Bombay and Braidwood have been told to leave if the path is clear.

If people are threatened by the fire, the advise is to take shelter in a solid structure to protect themselves from the heat.

Rural Fire Service Lake George district officer Darren Marks said last night the North Black Range Fire was burning "a few hundred metres" from the township.

"If you're in Braidwood it's an anxious time at the moment," he said.

"We are telling people to stay there, we're using Braidwood as a refuge. We're not getting those sorts of conditions like they did in WA and other places where you see towns getting wiped out."

The fire moved rapidly since 7pm when it was about 17 kilometres from Braidwood.

"It has done what we were unfortunately concerned it would do and it has just showered the area to the east of the forest with embers and sparks," Mr Marks said.

"It has started spot fires and in the bone-dry conditions we have at the moment those fires have taken hold really rapidly and started moving very quickly."

Mr Marks warned the fire could possibly push past Braidwood. He could not rule out the possibility it could meet up with the Currowan Fire, which has burned out 4793 hectares.

The "principle aim" of the firies was to make sure the fire didn't impact the village, Mr Marks said.

He said those in the vicinity of the bushfire should implement their bushfire survival plan, and if they are not prepared they should leave now, except for residents of Braidwood who were advised to stay and seek shelter.

"Areas around Butmaroo and Forbes Creek are likely to come under pressure overnight," he said.

READ MORE: Residents face the choice to leave, or stay and fight

The fire in Tallaganda National Park, which was started by lightning on Tuesday, covered around 10,000 hectares on the latest RFS estimate at 10pm Friday.

But Mr Marks said there was no "exact size" to the fire and that it was "uncontained on all sides" and "will continue in all directions".

The Kings Highway remains closed between Mayfield Road and Northangera Road. The roads to Araluen and Cooma are also closed.

Police are stopping east-bound traffic at Bungendore. Only local traffic is being allowed through. Locals are prevented from driving beyond Mayfield Road.

A couple of sheds have been lost in the blaze, Mr Marks said.

RFS Braidwood unit commander Matthew Talbott said the wind was variable.

"The wind is going north, south, east, west it is spinning around. I did see a lot of firetrucks come in so there are a lot of resources in town, worst case scenario," he said

"There are multiple helicopters and light aircraft in the air at the moment so best-case scenario nothing is going to happening.

"Long-term locals have said they have never seen a fire get close to town.

"The good thing about it where the fire is coming out of the bush there is lots of grassland that makes it easier to control. It's not 40-foot flames, it's five-foot flames so there is a lot more we can do to protect town then if the bush was right up in the urban interface."

The Rural Fire Service has advised:

NSW Rural Fire Service spokesman James Morris said conditions were forecast to ease on Saturday.

"Tomorrow we are not seeing significant winds but still we are seeing some winds and some warmth which will continue to fan this fire which is burning through grassland and dry fuels," Mr Morris said.

An emergency centre has been set up in the Braidwood Theatre and people have brought food to the centre.

One of the volunteers, Helen Conway, said the community was rallying. "We are being told to take shelter," she said.

Her home is made of wood but her neighbours, who have a stone house, told her she could shelter there. However, she had decided to stay at her own home to douse any embers.

At the Royal Mail Hotel in Braidwood, there were late bookings for rooms as people from rural properties took refuge. "We are getting a few emergency bookings," manager Gemma Garner said.

Ironically, a karaoke to raise money for the fire service was being held in the bar. She said that was continuing.

The ACT sent five fire trucks, with 23 personnel, on Friday and were planning to send another three trucks, making eight in all, on Saturday.

"The deployment will not impact on the level of fire protection in Canberra and surrounding regions," said an ACT Emergency Services Agency spokeswoman. The fire did not pose a threat to the ACT.

Smoke from the blaze could be seen over Queanbeyan and Canberra on Thursday evening and Friday morning, thanks to easterly sea breezes.

ACT Emergency Services Agency commissioner Georgeina Whelan said haze was expected to linger across capital into the weekend.

"We'll work closely with NSW and make sure we have situational awareness and we're expecting a change in the weather coming up with a drop in temperature."

Smoke from the fire has triggered more than 250 calls to triple zero from members of the public.

Ms Whelan said the calls were mostly people seeking information about the smoke and urged Canberrans not to call triple zero unless to report a fire.

"This impacts the wait time for triple zero call takers and triggers a deployment for emergency services when a response is not required," she said.

Mr Allan said the smoke haze in the ACT could also be from the Currowan fire burning in the Shoalhaven area, which has burnt more than 4600 hectares.

Health authorities warned people with heart or lung conditions to stay indoors during the smoke haze and to limit outdoor activity.

Air quality at all three air quality stations across the ACT has been marked as hazardous, the highest possible level.