Tourist icon, the Blue Mountains Botanic Garden Mt Tomah, re-opened on Monday January 13

Nature has been smashed along and beyond the Bells Line of Road - the way out to iconic Mt Tomah and Mt Wilson, as well as the villages of Bell, Bilpin and Dargan.

Signs are burnt, trees blackened and the area resembles a desolate, sobering wasteland.

Numerous charred trees are marked with a number, expected to come down if they haven't already been felled. The air still smells of charred timber in many places and Mt Wilson and Mt Tomah are green island pockets in a sea of brown.

Some 80 per cent of the Blue Mountains World Heritage Area has been affected, but there are signs of regeneration.

Tourist icon, the Blue Mountains Botanic Garden Mt Tomah, re-opened on January 13. The gardens have been closed since fires swept through on December 15.

Denise Ora, executive director Botanic Gardens and Centennial Parklands, said roughly a quarter of the gardens living collection had been affected.

"A quarter of the living collection was impacted by fire, including the conifer and North American woodland collections. Some areas are closed and safety of staff and visitors is our highest priority," she said.

The majority of the 180 hectares of conservation forest surrounding the formal garden areas was also burnt. The diverse wilderness has rainforest with numerous ferns, Eucalypt woodlands, small swamplands and a complex heathland that includes banksias, geebungs and mountain devils. Most of the garden's living plant collection and buildings including The Potager restaurant, accommodation, and wedding venue spaces are undamaged.

Ms Ora said she was extremely grateful to "our staff, local community and emergency services ... who dedicated time and expertise in dealing with the devastating fires". Staff have urged visitors to extend their time to help other businesses in the area.

On site dam water was used to save the property which is being restocked by fire services. The garden's temporary number is 0492 442 245 until lines are restored. There is limited parking and visitors are encouraged to come mid-week.

Last week Deputy Opposition Leader Richard Marles made a public plea for community support for businesses in the world heritage area, especially Katoomba, adding they "are just bleeding".

"They mightn't have been physically affected by fire but they have been affected. Go on a day trip to the Mountains ... they need it."