PRIME Minister Julia Gillard is expected to visit fire-ravaged parts of northwest NSW today.

Ms Gillard will visit Coonabarabran today, where the state's most destructive fire in more than a decade has raged this week.

The fire at Coonabarabran has burnt 42,000 hectares and on last night was burning along a 100km front after destroying 40 homes, 110 sheds, machinery, fences and untold numbers of livestock.

No lives have been lost in any of the state's scores of fires this month, but there are now concerns that blazes which have already threatened communities in the state's south may prove dangerous again when hot and windy conditions return tomorrow.

As residents returned to view the destruction around Coonabarabran yesterday, RFS Deputy Commissioner Rob Rogers warned the number of homes destroyed could rise as assessors entered burnt areas.

Mr Rogers said there were also revived concerns about fires that threatened homes in NSW's south last week, including the Deans Gap fire in the Shoalhaven and the Yarrabin fire in the Cooma-Monaro regions.

"It's looking like a severe fire danger day on Friday all the way from Sydney right down the eastern side of the ranges and then along the Victorian border past Wagga to the Riverina area," he said.

Last night, 81 fires were burning across the state, 11 of them out of control, including fires in the Gwydir, Namoi and Tamworth areas in the state's north.