Hunter under total fire ban on Tuesday due to "extreme" forecast

Temperatures are predicted to reach 36 degrees in Maitland and Singleton, 35 in Cessnock, Muswellbrook and Scone, 34 in Newcastle and 33 in Ports Stephens.

The NSW Rural Fire Service has also declared a total fire ban in the Sydney metropolitan area, the north-west, upper central west and far south coast.

Hunter council areas included in the total fire ban are Cessnock, Dungog, Lake Macquarie, Maitland, Muswellbrook, Newcastle, Port Stephens, Singleton and Upper Hunter.

Earlier on Monday there were out of control fires burning in Fern Bay and Martinsville. The grass fire at Fern Bay was situated at the firing range near the Stockton Trails.

The bushfire near Martinsville burnt through six hectares in Watagans National Park and was under control.

There were also fires under control at Morisset Park, Kitchener, Lovedale, Glen Martin, Howes Valley, Stroud and Coolongolook.

The total fire ban comes as the bushfire danger season officially stared on October 1.

RFS Commissioner Rob Rogers is worried this bushfire season will be the worst since 2019-20.

"We know there is community anxiety so we've got to balance between not not scaring people but making people take it seriously so they do some simple things to make sure they look after themselves and their family," he told 2GB.

"Clearly, fire season is here."

Mr Rogers expects an elevated fire risk until Wednesday but hopes rain forecast for later in the week will help ease conditions.

Temperatures across NSW soared into the 30s on Sunday - about 14 degrees above average in some areas - ahead of a cool change that arrived overnight on Monday.