Firefighters are batting over 70 out-of-control blazes across New South Wales, prompting total fire bans in nine regions.
The NSW Rural Fire Service (RFS) said there were still 100 fires burning across the state on Thursday morning with 73 of these uncontained.
"Crews have worked hard overnight to slow the spread of fire, undertake backburns and remove dangerous trees from roadways. This important work will continue today, supported by aircraft and heavy machinery," NSW RFS tweeted.
Total fire bans are in place for North Western, Northern Slopes, Greater Hunter, Central Ranges, Greater Sydney, Southern Ranges, Far South Coast, Monaro Alpine and Illawarra-Shoalhaven.
Today, Total Fire Bans are in place for nine areas. Additionally seven areas will experience Severe Fire Danger including the Greater Sydney, Greater Hunter & Illawarra/ Shoalhaven areas. Stay up to date. #nswrfs #nswfires https://t.co/4XQUho65mn pic.twitter.com/WKCCjj1O6j— NSW RFS (@NSWRFS) December 4, 2019
Strong westerly winds forecast for Thursday could push the Gospers Mountain fire as well as fires near Putty and Paterson further east, putting more properties at threat.
"We are asking people in the vicinity of these fires to have a plan and to know what they will do if that happens," an RFS spokesman said.
The Bureau of Meteorology says heavy smoke billowing from bushfires surrounding Sydney will linger in the city basin until Saturday.
Heavy smoke has been blowing into the city from a large fire near Warragamba Dam near the Blue Mountains, RFS said.
"An overnight temperature inversion will trap the smoke in the Sydney basin. This means smoke will settle in many areas and be very heavy," the RFS said in a statement.
"Smoke is also affecting areas including the north coast, Central Coast, Hawkesbury, Wollondilly, Queanbeyan and Shoalhaven areas."
The NSW environment department says this season's bushfire emergency has caused "some of the highest air pollution ever seen in NSW".
"Recently NSW has experienced elevated levels of pollutants as a result of smoke from the bushfire emergency, and dust caused by the severe drought," a spokesman said.
"NSW has experienced other periods of poor air quality that lasted several weeks, including the 1994 Sydney bushfires and the Black Christmas bushfires of December 2001 to January 2002.
This event, however, is the longest and the most widespread in our records."
Meanwhile, Queensland fire crews have been unable to beat back a large bushfire that is threatening lives and homes in the state's southeast corner near Toowoomba.
Conditions are getting worse and any residents of Forest Ridge and nearby Cypress Gardens who remain have been told to leave immediately or follow their bushfire survival plan as 24 fire crews attempt to control the blaze.
"Fire crews are working to contain the fire but firefighters may not be able to protect every property. You should not expect a firefighter at your door," the state's Rural Fire Service said on Thursday.
Part of the Gore Highway has been closed between Cypress Gardens and the BP at Captains Mountain since Wednesday evening as the fire rages southwest of Millmerran, a town not far from Toowoomba.
An evacuation centre is now open at the Millmerran Showgrounds.
A second fire significant fire is burning at Carneys Creek near the Queensland and New South Wales Border, with people there being told to get ready to leave.
Crews are fighting the fire on the ground and from the air.