Greater Sydney and surrounding areas were under a total fire ban as more than 30 bushfires and grassfires were burning this afternoon.

Sydney Airport hit 38.8 degrees by 2.30pm, with Bankstown, Camden and Penrith all nudging past 37.

The Bureau of Meteorology (BoM) said the extreme heat will impact eastern NSW and Queensland today and into the weekend.

The BoM said that heat and gusty winds could combine to produce elevated fire danger.

The NSW Rural Fire Service said there were about 32 bush and grassfires burning around the state at 12.30pm.

Seven of these were uncontained and may have been ignited from lightning strikes.

Some fires were burning near Hornsby in Sydney’s north, and Liverpool in the south.

Greater Sydney, the Greater Hunter and north-western NSW were all under extreme fire danger today.

NSW could possibly be hit by severe thunderstorms this afternoon, ahead of a southerly buster that should sweep through to the coast in the afternoon.

In Queensland, a band of heat will run from Cape York down to the south-east.

Maximum temperatures will range from the high 30s to mid-40s, the BoM said.

Overnight minimums will be in the high 20s.

The BoM warned the Brisbane metropolitan area, Biloela, Gympie, Ipswich, Julia Creek, Longreach, Oakey, Stanthorpe, Taroom and Winton are all in the crossfires of the December heat.

While NSW and Queensland simmer, Victoria will be partly cloudy with scattered showers and moderate temperatures.