The death of a Central Coast man who was defending his home from the bushfires is the worst outcome anyone could have wanted, Premier Barry O'Farrell says.
Mr O'Farrell says his sympathy is with the family of the man, who collapsed from a heart attack outside his Munmorah home and died in Wyong hospital on Thursday afternoon.
"That's the worst that anyone wants to happen and we send our sympathy to his family," Mr O'Farrell told journalists at Rural Fire Service headquarters.
The man's home was being threatened by the fire currently burning out of control in the Wyong area, which is the subject of an emergency warning and is believed to have destroyed a number of homes.
More than 170 firefighters supported by helicopters are at the scene.
RFS Commissioner Shane Fitzsimmons became visibly emotional as he addressed the media on Friday and had to pause to compose himself as he praised the work of firefighters.
"We've seen some very hostile fire ground situations right throughout yesterday; damage and destruction right across large parts of NSW," he said.
"We are expecting numbers to be in the hundreds when it comes to homes and buildings and infrastructure and we simply can't ignore the reality that there may be people still within their homes that may not have got out.
"We sincerely hope and pray that that is not the case, but we need to be realistic."
Mr O'Farrell will visit the Blue Mountains on Friday where he is expected to be joined by Prime Minister Tony Abbott.
Mr O'Farrell said properties across NSW remained under threat.
"It has been a difficult 24 hours and the bad news is that it continues with alerts on many of the fires that are still underway, with continued threats to property," Mr O'Farrell said.
He said he had no advice of any other people feared dead in the fires.
"What I do know is that there are two volunteer firefighters receiving medical attention and one of them currently being operated upon," he said.
"At this stage that's the extent if it."
Mr Fitzsimmons said the RFS was "not pursuing in any meaningful way reports of persons being unaccounted for".
He said RFS efforts were focused on the emergency warning blaze at Wyong burning towards Nords Wharf and Murrays Beach, while fires in the Blue Mountains had been downgraded to "Watch and Act," but were still volatile.
"Fire behaviour there is still quite dynamic," he said.
As well, there was a "mild degree of optimism" that rain could fall across some of the foregrounds on Tuesday, Wednesday and Thursday next week, easing bushfire conditions."Let's hope that's the case, but clearly unless it's something substantial there's a lot of active fire edge that's going to require many many weeks of effort," he said.