The state-owned logging company has warned in a letter to the environmental watchdog that hundreds of forestry jobs are at imminent risk because of the lack of available timber following last summer's bushfires.

In a letter to the Environment Protection Authority last September, the acting head of Forestry Corporation and a Regional NSW official said the creation of so-called site-specific operating conditions for hardwood forests affected by fire had been "challenging" and were not providing enough supply to meet industry needs.

"The restricted timber supply means significant impacts on the hardwood industry are now imminent, with only a few weeks remaining before job losses are expected," the letter by Anshul Chaudhary, Forestry Corp's acting chief executive office and Gary Barnes, the department secretary, said.

"It is expected that 155 direct jobs are at risk of being lost over the next few months in the South Coast and Eden regions," the letter said. "By the end of 2020, a further 460 direct hardwood industry jobs will be under threat on the North Coast, [with the impact] expected to be two to three times greater [if] accounting for indirect employment."