Residents and emergency services across NSW are preparing for hot, windy weather that could result in bushfires and dust storms on Tuesday, with a total fire ban declared for the entire state.

Most of Sydney, including the city and east, is forecast to reach a top of 37 degrees on Tuesday.

In Sydney's west, Penrith is set to reach 38 degrees, Liverpool is forecast to reach 37 and Campbelltown is set for a top 36.

Bureau of Meteorology forecaster Rebecca Farr said temperatures were expected to reach the high 30s in much of the state, hitting 40 degrees in the far north-west.