Hundreds of firefighters are battling the North Black Range fire after it jumped the Shoalhaven River west of Braidwood.

Key points: About 10,000 hectares have been burnt by fires which have broken out of the Tallaganda forest

About 10,000 hectares have been burnt by fires which have broken out of the Tallaganda forest Residents in the areas of Bombay, Little Bombay, and surrounding areas west of Braidwood are told it is now too late to leave

Residents in the areas of Bombay, Little Bombay, and surrounding areas west of Braidwood are told it is now too late to leave The Kings Highway is closed in both directions between Mayfield Road and Northangera Road

The fire burning in the Tallaganda National Park, east of Canberra, was downgraded from emergency level to watch and act as a southerly change saw conditions ease late Friday night.

The blaze is 12,000 hectares in size and just 1 kilometre from the town of Braidwood.

Following the downgrade, the News South Wales Rural Fire Service advised Braidwood residents to action their fire plan.

"If your plan is to leave, leave now if the path is clear," NSW RFS said on Twitter.

There have been no reports of properties lost on Friday evening.

Rural Fire Service district officer Darren Marks said several spot fires that broke from the Tallaganda National Park have now joined up.

"You can fairly safely assume that there has been a significant amount of fire that has gone through Little Bombay and Bombay," Mr Marks told ABC Radio Canberra.

"It has come out of the Tallaganda forest with a vengeance."

Loading

Residents in the 30 or so properties at Little Bombay and Bombay, west of Braidwood, have been told it is too late to leave and they should take shelter.

Braidwood, a town of about 1,600, has become the evacuation centre and residents there were also told late on Friday that it was too late to leave when the fire was at emergency level.

The RFS has called in an air tanker and established containment lines outside Braidwood to prevent the fire encroaching upon the town.

The Kings Highway has been closed between Mayfield Road and Northangera Road in both directions, and all roads into Braidwood are closed.

A total fire ban has been in place in the ACT and surrounding NSW for Friday, with the fire danger level listed as "severe".

Mr Marks said the fire — believed to have started with a lightning strike on Tuesday — was too dangerous to try to bring under control.

The fire was about 10,000 hectares large at Friday evening, according to the Rural Fire Service.

'Very surreal': Farmers enact fire plans

Residents in the immediate area have enacted their fire plans. ( ABC News: Tom Maddocks )

Helen Faulkner who runs a horse riding business in Bombay, said police were visiting homes in the area.

"They said we advise you to leave, but it is not an evacuation — if you stay no one can help," Ms Faulkner said.

She said despite having a fire plan ready, it was hard to keep calm as the fire front approached.

"It's just what they say is going to happen, you have got your plan, I enacted my plan, then you get to the smoke inhalation bit, then you go, 'I don't know what my plan is! I don't know what to do!'

"You feel like it is all fine, I can see the sun … but there is smoke off to my left and to my right, and there's plumes of smoke coming up, black plumes.

"At what point do you say, okay gang, let's go?"

Smoke from the Tallaganda forest fire rises over Braidwood, NSW. ( Supplied: Mark Barrington )

Farmer Ellie Merriman, who lives about 10km outside Bungendore on the edge of the Tallaganda forest, said she had been watching the fire burn on the other side of her boundary for days.

They had moved their livestock and were prepared to evacuate if the wind changed, she told the ABC.

"We're organised, we've got our fire plan, we've tested all our plans … we feel as prepared as we can be," she said.

"It just takes you so much longer that you think, moving horses, getting stuff together."

The family is now sleeping away from the property and returning during the day to monitor the situation.

"It's quite strange, very surreal, because we've been going through it for the past three days," she said.

The fire as seen from a property 10 kilometres outside Bungendore. ( Supplied: Ellie Merriman )

Smoke causes frenzy of calls from Canberra residents

The fire is about 40 kilometres away from Canberra, but a change in wind direction on Thursday night blew the strong-smelling smoke across the city.

More than 300 calls to triple-0 "consumed" the communications centre, triggering fire services to areas where no fires were burning, the ACT Emergency Services Agency Commissioner said.

On Friday morning, Canberra residents were being urged to refer to the NSW Rural Fire Service website and use the Fires Near Me app for advice about fires in the area, in a bid to alleviate the strain on the service.

Canberra was obscured by smoke on Friday, as a forest fire burned across the border in NSW. ( Supplied: Julian Taylor )

Many Canberrans, perhaps recalling the catastrophic 2003 bushfires that claimed both properties and lives, feared the worst when smoke blanketed the city.

"Just the smell of smoke brings back a lot of awful memories of 2003. Stay safe everyone," Maarama Kamira said on Facebook.

"Regardless where it's from it feels unsettling," another Facebook commenter, Lauren Irvine, said.

But the advice from authorities was to keep calm, urging only people who see fire, and not smoke, to call in.

"I think it's a combination of concern from our community and also the fact that we've asked our community to remain vigilant throughout this fire season," ESA Commissioner Georgeina Whelan said.