A total fire ban has been declared and school students kept home for the day on NSW's South Coast as temperatures soar across the state.
The NSW RFS upgraded the Far South Coast to a catastrophic fire danger rating at midday due to stronger than forecast winds.
'Watch and Act' alerts have been issued for two fires, a grassfire at Eden on the south coast and a bushfire 30km south of Bombala in the Bondi Nature Reserve.
The fire at Eden was brought under control after about 40 minutes but residents have been warned to stay alert and monitor conditions.
Firefighters are also responding to blazes in the Lake Macquarie area near Newcastle and Wallacia on the outskirts of Sydney.
The NSW Rural Fire Service warned of fire danger conditions as an unusual spring heatwave delivers temperatures above 30 degrees in Sydney, on the south coast and in central western NSW.
The NSW Department of Education has temporarily closed 20 schools facing elevated bushfire risk on the South Coast on September 19.
And a total fire ban has been declared for Greater Sydney and the Far South Coast.
The NSW Rural Fire Service has more than 500 personnel responding to 61 fires burning statewide - 13 which were not yet contained as of 9am on September 19.
The Bureau of Meteorology's Angus Hines said the South Coast was facing heatwave conditions through to Wednesday.
"A heatwave is a three-day stretch where the daily high temperature and the overnight low temperature are both significantly above average for the time of year," he said.
"If you're outdoors frequent shade and water breaks, check in on your friends, family and neighbours and don't forget to give lots of water to your pets as well."
Mr Hines said Sydney was expected to reach 34 degrees on Wednesday ahead of a cool change bringing the temperature down for Thursday.
"On Wednesday we're going to see warm, windy weather around Sydney and the Greater Hunter area with extreme fire danger forecast in those regions," he said.
Elsewhere parts of Western Australia, the Northern Territory and Queensland are also seeing temperatures in the mid 30s.
The NSW Department of Education has closed the following schools for September 19 in consultation with the NSW Rural Fire Service.
The Far South Coast has an extreme fire danger rating with mercury forecast to hit 35 degrees at Bega, Merimbula and Bermagui and northwesterly winds.
"We encourage parents and carers to always follow the advice of police and emergency services during periods of heightened bushfire risk," a statement from the department said.
IN OTHER NEWS:
Sign up for our newsletter to stay up to date.