Fire authorities have brought in a second air tanker to battle what is now a 2000-hectare bush and grass fire burning out of control near Tarago, 70km northeast of Canberra.
The NSW Rural Fire Service says fire fighters are protecting isolated rural properties in the area as the fire moves in an easterly direction.
It has now reached Goulburn Road.
RFS spokesman Greg Allen said there was no confirmation of property damage or loss at this stage and no reported injuries.
The air tankers Thor and Southern Belle are assisting the 95 fire fighters on the ground while an emergency warning has been issued for homes near Mount Fairy Road.
Residents near Mount Fairy Road are being told to shelter in place as the fire front approaches while those near Goulburn Road and Boro Road should implement their survival plans.
The Goulburn to Queanbeyan rail lines have been closed.
Bungendore Road, Mount Fairy Road and Goulburn Road have been closed to traffic.
Strong winds are expected to make it more difficult for firefighters to battle the blaze.
Temperatures in the area hit 36C today.