A total fire ban will be in force on Thursday, with the Rural Fire Service expecting the danger rating could reach 'severe' in Maitland and across the wider Hunter.
Warm and windy conditions forecast across NSW prompted the ban in the Greater Hunter, Far North Coast, North Coast, New England, Northern Slopes and North Western regions.
'Severe' fire danger is expected in the Cessnock, Dungog, Lake Macquarie, Maitland, Muswellbrook, Newcastle, Port Stephens, Singleton and Upper Hunter areas, RFS said in a statement on Wednesday afternoon.
The Bureau of Meteorology has forecast a top temperature of 29 degrees in the valley, with north to northwesterly winds of 15km/h to 20km/h turning westerly up to 45km/h through the morning.
The prediction is similar for Newcastle, where a top of 28 degrees is expected and westerly winds up to 40km/h are predicted through the morning.