Fires in NSW have burnt almost 5.5 million hectares since July, leaving a mounting damage bill for removal of dangerous trees along hundreds of kilometres of major roads and the deployment of almost 100 generators and satellite phones to restore basic services.

The NSW Rural Fire Service said more than 60 fires were still burning as of Monday, with 2000 personnel still out in the field trying to contain at least 20 of them. The 5.45 million hectares tally so far included fire perimeters stretching 26,612 kilometres - or more than twice the distance between Sydney and Los Angeles.

A fallen tree on the Kings Highway linking Canberra to the NSW coast. The road that was closed for more than a month because of the bushfires. Credit:Kate Geraghty

Nationally, the tally is about 12.2 million hectares, excluding the Northern Territory with its regular savanna burning. Trent Penman, a bushfire behaviour researcher at Melbourne University, said a paucity of accurate fire maps from earlier eras makes it difficult to say if any fire season had burnt more of Australia.

"It's certainly a significant and rare event," Professor Penman said.