Although parts of the Illawarra are forecast to escape the extreme heat on Friday, with the maximum predicted to be 32 degrees in Wollongong and 35 in Albion Park, temperatures are expected to soar into the 40s across other parts of NSW. 

Bowral is tipped to reach 37 degrees while 38 degrees has been forecast for Nowra.

The tiny outback town of White Cliffs is due to peak at 47 degrees, while Bourke will reach 46 degrees - its fourth day in a row above 40 degrees. Dubbo is tipped to reach 43 degrees, and western Sydney 42 degrees.

The forecast of unexpectedly strong north-westerly winds has prompted the NSW Rural Fire Service to increase the areas with total fire bans from 11 to 12.

The Illawarra has a ‘very high’ fire danger rating, but is not one of the areas with a total fire ban.

Areas with a total fire ban include the Greater Sydney area, which includes the Blue Mountains and the Central Coast.

Commissioner Shane Fitzsimmons from the NSW Rural Fire Service said that the strong winds, low humidity and high heat would combine to pose a deadly bushfire risk. 

"When you have these hot, dry, windy conditions on top of a very dry landscape, which is what we have in NSW, you have a landscape that is very susceptible to fire," he said.

"We are seeing very high temperatures right across NSW, dry conditions because of strengthening winds, as well as the humidity [dropping] below 20 per cent."

A total fire ban prohibits fires from being lit in the open and there are heavy penalties in place for those who do. An on-the-spot fine fetches $2200, and fines for discarding lit cigarette butts increase on total fire ban days from $450 to $1320, Commissioner Fitzsimmons said. 

The 12 areas with bans include Greater Hunter, Greater Sydney, Central Ranges, North Western, Upper Central West Plains, Lower Central West Plains, Southern Slopes, Eastern Riverina, Southern Riverina, Northern Riverina, South Western and Far Western. 

- with smh.com.au