Small townships west of Sydney have come under renewed threat from two major Blue Mountains bushfires.

Warnings for the State Mine fire raging between Lithgow and the mountains and the nearby Mount York Road fire at Mount Victoria are being lifted to the top emergency rating, the Rural Fire Service said on Thursday.

Flames from the Mount York Road fire have breached containment lines north of Bells Line of Road and are bearing down on the community of Mount Wilson.

Residents there are being warned to shelter in place.

“There’s also some concern, depending on how quickly the fire spreads, for communities at Mount Tomah,” an RFS spokesman said.

Specific advice for Mount Tomah residents will be issued if they come under threat.

An RFS spokesman later told reporters Mount Irvine and Mount Wilson residents would also need to shelter in place as the fire approached because access roads were up in flames.

“It’s not safe to leave,” he said.

Residents in Mount Tomah and Berambing still had time to get out, he added.

“If you’re not properly prepared and want to relocate, you need to head east towards Bilpin,” he said.