Catastrophic fire conditions, including oppressive temperatures and high winds, have seen NSW lose its first home in the bushfires.
Dozens of homes were under threat in NSW on Tuesday as firefighters battled 135 blazes in 40-plus temperatures and conditions officially rated as "catastrophic".
On Tuesday night the fires claimed the first home, with one property confirmed to have been lost in Jugiong near the ACT border.
RFS Commissioner Shane Fitzsimmons said a large amount of damage had been done to infrastructure in pasture country across the state, with 1000 head of stock lost.
"We've still got many hours of very difficult conditions being faced for NSW. That's tonight alone, let alone looking into tomorrow," he told ABC Television.
"Particularly as this southerly change moves northward, we can expect some fairly intense and erratic weather behaviour."
More than 1600 firefighters were in the field or on standby on Tuesday night, after a day in which blazes, fanned by winds over 70km/h, burnt more than 60,000 hectares of grass, scrub and bushland.
Catastrophic fire danger ratings remain in place in the Illawarra/ Shoalhaven region, as well as the Southern Ranges and the Eastern and Northern Riverina.
Severe and Extreme warnings are affecting much of the rest of NSW.
Although almost 30 fires remain uncontained on Tuesday evening there had been no reports of loss of life.
"We should simply breathe a sigh of relief if we get to 2 o'clock tomorrow morning and nothing serious has happened," Premier Barry O'Farrell told the Seven Network.
Sydney recorded a peak temperature of 42.5 degrees, with the heat set to remain as high as 30 degrees late at night and into Wednesday morning.
Thirty homes were threatened by a fire 12km east of Cooma - 20 in the Kybeyan Valley and 10 around Mount Forest Road in the Cooma-Monaro area.
At the township of Tarcutta, in southwest NSW, a bushfire burnt through 500 hectares and surrounded the town.
But by the early evening the Hume Highway was reopened in both directions with the immediate threat to the village easing.
RFS spokesman Brendan Doyle urged people to remain vigilant as southerly winds shift fires.
"If the southerly wind changes, that may push the fire back on to the town," he told AAP.
At Wandandian, south of Nowra, the Princes Highway was closed in both directions on Tuesday night as a southerly wind change saw a large bushfire burn out of control.
The fire which had burned through more than 1500 hectares was about two to six hours from properties.
Three youths were taken into police custody on Tuesday afternoon after a suspicious fire in Shalvey in Sydney's west.
Firefighters contained the blaze which affected about 10 hectares of bushland.
A total fire ban will remain in place across NSW on Wednesday.
The Salvation Army has launched the Australian Disaster Relief Appeal in response to the bushfires in communities in NSW and other communities across Australia.