Hundreds of Macarthur firefighters aiding the bushfire threat in the Sutherland and Liverpool areas remain on alert with the risk of high winds and temperatures on Monday.
Residents endured a second nervous night on Sunday as the fire that's so far blackened about 2500 hectares continued to rage, with hundreds of firefighters working to contain the blaze.
The fire, which began on Saturday afternoon and may have been deliberately lit, was fanned by strong winds on Sunday and approached suburban streets.
Conditions have eased with winds at about half the strength they were on Sunday as the fire continues to burn in a south easterly direction towards Barden Ridge. Winds are predicted to pick up later on Monday.
High temperatures also remain a cause for concern, Rural Fire Service Deputy Commissioner Rob Rogers warned.
"Still quite a difficult day ahead (on Monday)," he told Nine Network.
"I think we've got a long way to go before we're out of the woods."
The RFS cautioned that while the threat had eased, residents in the areas of Voyager Point, Pleasure Point, Sandy Point, Alfords Point, Barden Ridge, Illawong, Menai and Bangor should continue to monitor the situation and be prepared to activate bushfire survival plans should conditions change.
Heathcote Road remains closed between Macarthur Drive and New Illawarra Road, while Old Illawarra Road at Barden Ridge has re-opened.
RFS spokesman Greg Allan said on Sunday some properties had been damaged.
"We have had reports of impact on properties in west Menai and Barden Ridge but our crews at the moment are solely focused on fighting the fire," he told AAP.
The fire tore through the Holsworthy military range and more than 500 personnel from the Rural Fire Service, Fire and Rescue NSW and the Australian Defence Force battled to protect properties.
The blaze was downgraded from Watch-and-act to Advice about 2am on Monday.
“Gusty winds and very dry bushfire fuels caused by prolonged higher than average temperatures have combined to create erratic and volatile bushfire conditions,” Illawarra RFS Manager Superintendent Greg Wardle said.
Macarthur RFS tankers, fire ground commanders and incident management personnel responded to the emergency late Saturday afternoon.
Recently the Illawarra Zone suspended private pile burning and hazard reduction due to the underlying dry conditions and high winds.
“We are very thankful that the local community followed our request not to conduct any pile burns and as such helped us to avoid any major issues in the past week,” Superintendent Wardle said.
Firefighters have taken advantage of the conditions to do a back burn along Heathcote Road near Pleasure Point as well as in areas of the Holsworthy military base.
A large number of firefighters remain on the ground working to slow the spread of the fire.