Multiple fire crews are on scene at Lomas Lane, Nulkaba where a grass fire broke out on Sunday afternoon.
A NSW Rural Fire Service spokesperson said at 2pm that four trucks were on scene, with more on their way to assist.
The fire broke out just before 1.30pm. While it is on the same road as the Hunter Valley Zoo, the RFS spokesperson said the blaze was at advice level and was not a threat to properties.
He said crews had managed to knock down the head of fire - the fastest spreading part - and were working to contain the rest.
The size of the fire is not yet known.
For further information and updates, visit the Fires Near Me section on the RFS website.