The North East Forest Alliance is compiling data from the recent bushfires to present a case to UNESCO that world heritage forests - including the Barrington Tops National Park - are in danger.

The Barrington world heritage area is part of a system of ancient forests that were burnt in the recent bushfires.

"We're concerned the Gondwana rainforests of Australia are declining. And the fires are the latest symptom of that," forest alliance spokesman Dailan Pugh said.

Ecologists believe the recent drought and bushfires could be the start of NSW's ancient forests drying out in a world of "global heating".

"It would be an environmental disaster if we lose these heritage forests," Mr Pugh said.

The Barrington Tops, for example, is "the major source of water for the surrounding countryside".

"These wetter forests transpire water into the atmosphere and then the streams.

"They help keep the surrounding area wetter by releasing moisture into the atmosphere to form clouds and rain. They help keep the climate cooler. They have immense benefits."

Among these are economic benefits.

"The Barrington Tops certainly is a major tourist attraction and generates a lot of revenue for the surrounding community," he said.

The Newcastle Herald reported on Monday that about 10 per of the Barrington Tops National Park world heritage area was damaged in the recent bushfires.

The area of affected rainforest - which is part of the ancient Gondwana system - covers 4011 hectares, NSW government data shows.

Ancient world-heritage areas stretch in pockets from the Barrington Tops to the Gold Coast. They are the last remnants of the supercontinent Gondwana, which broke up about 180 million years ago. Usually these forests are too wet to burn.

A government environment spokeswoman said 54 per cent of the NSW parts of the Gondwana world heritage areas had been affected by the recent bushfires.

Mr Pugh said "bell miner associated dieback" was also threatening the forests. The condition causes trees to die from the top down.

"We're worried that the fires will exacerbate that problem," he said.

The condition is caused by the proliferation of aggressive bell miner birds dominating in declining areas of forest and psyllid insects feeding on eucalyptus trees.

"The forests are dying and not recovering [from the condition]. They're getting worse over time.

"Barrington was one of the areas where it was identified early on, adjacent to the world heritage area, particularly in Chichester State Forest."

As for the recent bushfires in the Barrington, Mr Pugh said "there is a need for recovery action".

"There needs to be active on-ground work done as soon as possible to stop the spread of lantana.

"Lantana is a big worry."