An "enormous amount of fire" is still burning across New South Wales after a "very long and volatile" night, which left dozens of properties either damaged or completely destroyed.

A southerly change swept through fire-affected areas, spreading the blazes and making them behave erratically. The immediate risk to people's homes did not pass until the early hours of the morning, around 3am.

Speaking to reporters this morning, NSW Rural Fire Service Commissioner Shane Fitzsimmons said "widespread damage" had been reported.

"The reports are indicating another heavy toll, unfortunately, with estimates that property loss could be in the dozens of buildings, including homes, outbuildings, sheds and businesses. And the destruction ranges from places like Lithgow, Dargan, places around Balmoral and out towards Buxton," Mr Fitzsimmons said.

An elderly man is missing after staying in an attempt to defend his home in Dargan. That residence is believed to have been consumed by flames, and authorities are now searching for him.

"I commend the firefighters in the community for their extraordinary response and their efforts yesterday in awful conditions," Mr Fitzsimmons said.

The danger may have eased, but it hasn't passed.