The long weekend will see large parts of central and eastern New South Wales hit with another severe heatwave as the state heats up again after a brief respite, with parts of the Sydney basin facing temperatures up to six degrees hotter this Australia Day than in 2018.

The Bureau of Meteorology's (BOM) heatwave service shows widespread low intensity heatwaves forming across central and eastern Australia this week, with temperatures rising to severe levels along the east coast of NSW on Friday, Saturday and Sunday as the hot weather shifts across from South Australia.

Beating the heat: Beachgoers cool off at Coogee on Tuesday. Credit:James Alcock

A BOM spokesperson said this weekend's heatwave, while still "quite severe", is unlikely to see as many records tumble as last week's prolonged extreme heat.

However, "we might see a few late-season overnight minimum records in the central west."