An emergency bushfire warning has been downgraded to a watch and act for a fire burning in the Wollemi National Park and Putty State Forest, near Singleton, but properties are still at risk.
The New South Wales Rural Fire Service (NSW RFS) warned that the fire is burning under strong westerly winds, and under "severe fire danger conditions".
A spokesman for the NSW RFS, Greg Allan, said the fire had already burnt through 7,000 hectares.
It is still not safe for residents who have evacuated to return to the area, the RFS said, and firefighters are liaising with those who chose to stay and protect their properties.
RFS Deputy Commissioner Rob Rogers said the bush is very dry and the fire is burning very aggressively.
"I think it's going to be a very long night for firefighters and residents," he said.
"Conditions are not expected to ease until tomorrow morning."
The NSW RFS said 11 waterbombing aircraft were assisting firefighters to battle the blaze.
Due to the conditions and different terrain, the fire is throwing a lot of embers kilometres ahead of the blaze.
