NSW bushfire upgraded to emergency

An emergency warning has been issued for a bushfire burning in northwest NSW.

The NSW Rural Fire Service (RFS) issued the emergency alert for the Oxley Crossing blaze northeast of Coonabarabran at 3.55pm (AEDT) on Monday.

"A bushfire is burning in a south easterly direction towards the township of Rocky Glen," the RFS said just before 4pm.

"If you are not prepared, leave now in an easterly direction towards Gunnedah.

"If you are staying with your property, make final preparations now and seek shelter as the fire front arrives."

The fire has already burnt through more than 100 hectares, a year after major bushfires threatened homes and an observatory in the region.

The Transport Management Centre said the Oxley Highway was closed in both directions about 25km east of Coonabarabran.

Eastbound motorists were being diverted at the Newell Highway to travel via Narrabri while westbound motorists are diverting via Black Stump Way.

Ninety-nine fires were burning across the state on Monday morning, with 26 of them still out of control.