Rural Fire Service Commissioner Shane Fitzsimmons and NSW Premier Barry O'Farrell inspected the bushfire damage at Winmalee this morning.
They held a joint press conference at 11am, confirming the fire near Winmalee, Yellow Rock and Hawkesbury Heights was currently not threatening homes but was not under control either and would keep burning for days.
Commissioner Fitzsimmons said more than 100 firefighters were conducting backburning and mop up operations surrounding the main fire front, more than 6km of backburning was done last night and into this morning "and we expect they will be busy at this, 24 hours a day, for many days yet before they can safely say this fire is contained".
"We've got [investigative] teams out in the field today at all these fires and their focus is to look at where and how these fires started.
"That will include detailed analysis of the effect, if any, as a result of hazard reductions occurring in this area in the last week or so.
"What we've also got are teams out in the field today doing a more forensic analysis of the damage toll.
"We did have reports initially that a home was destroyed up here in Winmalee, that appears not to be the case, albeit that home has suffered some damage.
"At this stage it would appear two people's homes may have been destroyed in the fire in Marsden Park."
Commissioner Fitzsimmons said yesterday's weather conditions exceeded what was forecast in terms of temperature, humidity and wind speed.
"That presented challenges that were otherwise unforeseen and to have a number of fires start off in relatively close proximity to one another, to see resources coming from all over the place, firefighters from greater Sydney descend on the area and try to protect people and their property, I think was outstanding.
"Looking at the detailed maps here with our incident controller David Jones, we do know that adjacent to the areas of Winmalee that we had hazard reduction completed in May 2013.
"The [current] fire has not travelled through that area, so that's indicative of the effectiveness of hazard reduction and the protection it provides to communities adjacent.
"Most importantly, men and women are dedicating weekdays, weeknights and weekends of their time to get this really important, complex and difficult work done. It does make a difference.
"If it wasn't for the firefighting efforts, particularly those on the ground working from the back of their fire engines, if it wasn't for those community members who were prepared and acted on their Bushfire Survival Plan, and with the support of the [water bombing] aircraft, then clearly the result of the damage would have been worse."
Commissioner Fitzsimmons said four firefighters were taken to hospital yesterday but all have been released.
"Injuries ranged from superficial burns to heat exhaustion. Also, [a man's] chest pains fortunately turned out not to be regarded as a heart attack but more stress or anxiety related and [another] firefighter was bitten by dogs [in a property he was protecting] that were panicked.
"A number of other firefighters were treated for smoke inhalation at the scene by paramedics."
Premier O'Farrell stressed the importance of NSW's increased hazard reduction program "because the alternative is disaster.
"Over the past financial year there's been 280,000 hectares [of hazard reduction burns] across the state, up in the Blue Mountains I think it was 14,000 hectares last year and 3,500 hectares so far this financial year.
"We are deliberately encouraging as much hazard reduction as possible because when you don't undertake hazard reduction you leave the fuel load as it is and it grows."
Mr O'Farrell said he is keen to get to the bottom of the cause of the fires but nobody should prejudge that or "believe that there is any alternative to undertaking hazard reduction except bringing further death and destruction".
Mr O'Farrell thanked all the firefighting volunteers and their families for their time, effort and dedication.
He also said one of the earliest starts to the fire season in years should be a wake-up call to all residents of the state.
"It means there are additional responsibilities on everybody because people can't afford to wait until summer to start taking the usual fire protection measures."