The 47-year-old man died of a cardiac arrest on Saturday night while defending a friend's rural property near Batlow, southwest of Canberra.
There were just under 150 bushfires burning in NSW on Sunday morning, with emergency warnings issued for blazes in the southern highlands and on the south coast near the NSW-Victoria border.
Early reports indicated hundreds of properties had been damaged or destroyed after bushfires tore through NSW on Saturday, NSW Rural Fire Service Commissioner Shane Fitzsimmons said.
"It was an awful day yesterday. It was a very difficult day," he told reporters at RFS headquarters on Sunday morning.
"We are getting reports that the property losses, the damage and destruction, is likely to be numbering in the hundreds as a result of yesterday's fire activity and fire spread.
"We're talking a considerable number, a considerable impact."
There were reports of properties being lost in the southern slopes, the NSW south coast and the southern highlands regions.
The 47-year-old man who died had travelled down from Goulburn to help a friend in Batlow, Mr Fitzsimmons said.
Thirteen bushfires burnt at an emergency level on Saturday.
"That's second only to what we saw a couple of months ago, where 17 concurrent fires were burning (at emergency level)," Mr Fitzsimmons said.
Although fire weather has eased on Sunday, conditions remained "volatile" and dynamic at a number of fire grounds, Mr Fitzsimmons added.
Two emergency warnings remain in place.
NSW Premier Gladys Berejiklian said as of Sunday morning there were no people missing in the fires.
"That's a huge relief. Our mission yesterday was to save life. Our mission during the night was to save human life," she told reporters.
"That's not to say we don't get bad news during the day, but indications at this stage there's no unaccounted people in NSW. That's the best news we could have hoped for this morning."
Two firefighters suffered smoke inhalation overnight while protecting water infrastructure in the south coast town of Milton.
A statewide total fire ban is in place on Sunday while a week-long state of emergency - the third in as many months - continues.
Prime Minister Scott Morrison was on Sunday criticised for not alerting fire authorities before announcing the defence force would be deployed to help bushfire recovery efforts.
NSW Rural Fire Service Commissioner Shane Fitzsimmons said he was disappointed about the lack of notice and expressed concern to the prime minister's office and received an apology.
Situation in Victoria
More evacuation orders have been issued to Victorians overnight as massive blazes continue to ravage the state's east.
People in Dandongadale, Freeburgh, Wandiligong and surrounding areas in northeast Victoria were advised to leave overnight as a southwest wind change fanned bushfire flames.
Dozens of fires were burning in Victoria as dawn brokee on Sunday, 11 of which were subject to emergency warning, the highest alert level.
More than 900,000 hectares of land has been overrun by flames, with about 110 properties and 220 outbuildings razed so far.
Temperatures soared to the early and mid-40s in parts of East Gippsland and northeast Victoria on Saturday, with total fire bans in place for a swag of weather districts.
More than 70 new fires were sparked in the 24 hours to 6pm on Saturday.
Cooler conditions, lighter winds and a lack of lightning on Sunday are expected to bring some relief to firefighters.
The mercury is forecast to peak in the early 20s in East Gippsland, with rainfall of about 20ml expected later in the day.
In the northeast, temperatures could hit the late 20s in some parts, with some rainfall - albeit it likely less than 5ml - expected.
"That will help subdue the fire activity," Bureau of meteorology senior meteorologist Dean Stewart told AAP.
Despite the shift, Premier Daniel Andrews has urged people to heed warnings and not be complacent.
"Lives can be lost if people don't follow the instructions they're given," he told reporters.
The towns of Omeo and Swifts Creek in East Gippsland as well as Corryong near the NSW border are among those to have been under threat.
About 50 people were evacuated from Omeo by Chinook helicopters on Saturday but about 300 chose to stay in the township, Emergency Services Minister Lisa Neville confirmed.
The evacuees were flown to Bairnsdale on the western side of the fires, before being transported to Sale.
In Gippsland, firefighters have been working to save critical infrastructure and the Country Fire Authority's Andy Gillham said they were "in for the long haul".
"This is a marathon event and we expect to be busy managing these fires for at least the next eight weeks."
The fires have already killed Buchan man Mick Roberts and Maramingo Creek man Fred Becker.
About 70% of the 100,000 population of the fire-impacted East Gippsland have fled.
Major highways have been closed for days, phone and powerlines are down, and residents have been told not to drink tap water amid contamination fears.
After the sky turned red, then black at Mallacoota on Tuesday, people from the town are reporting the same thing has happened on Saturday.
Naval vessels plan to re-stock and return to the township to evacuate more people.
About 500 people are at a relief centre in Bairnsdale and there is an overflow centre at the local racecourse.
A state of emergency remains in place for Victoria throughout next week.
