The NSW Rural Fire Service is advising residents to prepare their properties ahead of worsening conditions, with soaring temperatures and dry winds forecast to elevate the bushfire danger in parts of the state.
Two firefighters were killed and as many as 100 houses destroyed when bushfires ripped through NSW on Thursday and Saturday last week.
Firefighters have used milder conditions in recent days to try to strengthen containment lines and more than 1400 were working on Boxing Day to slow the spread of fire.
RFS spokesman Ben Shepherd said they had done great work through Christmas while the conditions remained favourable.
“The weather has been for once a little bit more in our favour but it’s still going to be a potentially difficult day come next week once we start to see that bad fire danger set in,” Inspector Shepherd told AAP on Thursday.
There were nearly 70 bush and grass fires burning across the state about midday, with 28 yet to be contained.
“Take some time today to prepare your property for the forecast worsening conditions this weekend and early next week,” the RFS tweeted.
Bureau of Meteorology duty forecaster Rose Barr said a severe heatwave bringing severe to extreme conditions would start building in southern parts of NSW on Thursday.
“Between Thursday and Saturday we are starting to see severe heatwave conditions in the southern parts of the state, extending over a more significant area of NSW into the weekend and next week,” she told AAP.
“Some areas are forecast to reach extreme heatwave conditions,” she added. “With the increasing heat and winds, the fire danger will worsen into the new week, with Monday and Tuesday most likely to be the most significant fire weather days.”
The heatwave is expected to also affect the northern parts of South Australia. But Adelaide will be spared with a top of 33C forecast before soaring to 39C on Friday. As of early Thursday, a bushfire that was ravaging the Adelaide Hills has been downgraded to the lowest warning level.
More than 1700 firefighters were in the field on Christmas Day, slogging away to strengthen containment lines before the dangerous weather arrives.
Fire and Rescue NSW Commissioner Paul Baxter on Thursday thanked firefighters who worked through Christmas, noting their commitment, dedication, professionalism and selflessness.
“Last week, we had a near miss when a motorist hit one of our firefighters on the incident ground,” Mr Baxter went on to say in a message posted to Facebook.
“I want to remind members of the community that when you are on the road and see emergency vehicle lights flashing, please slow down and give our crews space. It’s safer for you and safer for our crews.”
Fire danger ratings are very high on Thursday for the ACT, the greater Hunter, the central and southern ranges, the northern and southern slopes and northwestern NSW.
There is a high fire danger rating from the far south coast up to Sydney, with a low-moderate danger rating in western parts of the state.