A total open fire ban is in place throughout a swath of the Western Plains as the Rural Fire Service (RFS) ask farmers to stop harvesting.

The service issued an alert this morning for growers in the Bogan, Coonamble, Walgett and Warren shires to stop and check local weather conditions before deciding if it's safe to continue harvesting.

A total fire ban is in place for the Coonamble, Warrumbungle, Walgett, Brewarrina and Bourke shires, which are forecast to be lifted with an easing in fire risk tomorrow (23 October).

In the Warrumbungle National Park, 21 walking tracks and remote campsites have been close from 4:00pm Tuesday 21 October to 9:00am Thursday 23 October due to fire risk.

Weather areas under total fire ban as at midday on 22 October. [IMAGE: RFS]

"All campfire and solid fuel (wood, heat beads, charcoal, briquettes, hexamine) and liquid fuel (petroleum, oil, methylated spirits, kerosene) barbecues and stoves are prohibited," the NSW Parks and Wildlife Service said on their website.

Gas barbecues installed by NPWS may be used for cooking, as long as it is under the direct control of a responsible adult, is clear of combustible material within two metres at any time it is operating, and there is an immediate and continuous supply of water available.

Visitor-owned gas and electric barbecues and cookers are generally prohibited.

There may be exceptions if you contact the local park office in advance for permission.

Gas and electric cookers are permitted within a caravan or three-sided enclosed annex of a caravan.

Weatherzone said "the searing outback heat will begin to dissipate overnight (Tuesday), with Wednesday maximums in the low-to-mid 30s in all of the locations mentioned above.

"That’s still relatively warm for this time of year, but it’s around 10 degrees down on Tuesday’s extremes."

NSW Health has advised the elderly and those vulnerable to heat to stay indoors.

Locals can stay up-to-date with fire bans on the RFS website.