Strong winds have whipped up bushfires in NSW's north west, the southern tablelands and in Sydney's Royal National Park amid hot and dry conditions.
Smoke continues to blanket southern Sydney and the NSW south coast as strong winds fan blazes in the Royal National Park and across the state.
The fire along Sir Bertram Stevens Drive, which is believed to have been deliberately lit, has ripped through more than 2000 hectares of land since Saturday.
Firefighters on Monday afternoon were trying to burn out the final area amid continued hot and dry conditions.
Authorities are hoping to have it contained by Tuesday.
Winds and back-burning operations have kicked up the amount of smoke in the area, which is expected to hang about for the rest of Monday.
"That smoke has been affecting south-western Sydney, the Illawarra and further south along the coast but there's no threat to properties at this stage," a NSW Rural Fire Service spokesman told AAP.
The park - which was filled with hikers and tourists when the fire broke out on Saturday - remains closed.
NSW RFS Commissioner Shane Fitzsimmons said it appeared the blaze was deliberately lit.
"You don't need a degree to work out that something very suspicious has occurred there," he told Sydney's 2GB radio.
"Thank goodness, people have got cameras and other devices in their hands these days."
Strengthening winds have also whipped up a fire in the Pilliga Forest between Coonabarabran and Narrabri in NSW's north west.
The fire is almost 55,000 hectares in size however no homes are currently under threat.
Crews on the ground and in the air are working to slow the spread of the fire as conditions worsen.
"They're looking at the fact the smoke plume might be generating a bit of thunderstorm activity, which could be interesting," the spokesman said.
Another blaze at Bannaby in the Southern Tablelands was on Monday afternoon upgraded to a 'watch and act', as strong winds put pressure on containment lines.
The 1800-hectare fire is out of control, with firefighters helping residents prepare their properties along a number of roads.
Total fire bans have been declared for the Southern Ranges, Central Ranges, Greater Hunter and Greater Sydney.
The ban is expected to continue in parts of NSW on Tuesday, with very high and severe fire danger forecast for much of the state.