A state of emergency has been declared across NSW, with warnings dire bushfire conditions could force mandatory evacuations and leave homes isolated.
More than 200 properties have already been destroyed in blazes that have scorched the Blue Mountains, the Southern Highlands and the Central Coast since Thursday.
On Sunday bad times were again foreshadowed, with Premier Barry O'Farrell declaring a state of emergency.
"The RFS (Rural Fire Service) Commissioner has advised weather conditions over the next few days will deteriorate significantly and that there is potential for a significant and widespread danger to life and property across the state," Mr O'Farrell said.
The declaration will now give emergency services a range of powers, including the ability to direct people to evacuate homes, and shut down electricity supplies.
It comes after an emergency warning was issued for the township of Bell in the Blue Mountains on Sunday, with people told to head for Lithgow where an evacuation centre has been set up.
The fire, which has already scorched almost 38,000 hectares of bush and scrub, was also expected to see people in Bilpin village isolated, with residents warned they might face days without electricity.
But despite the threat, resident Craig Jones said most would probably stay put to defend their homes.
After spending two days helping save his wife's cafe in Bell, Mr Jones says he's only cried once.
That was when he discovered a lone, red waratah in the cafe's garden had survived Thursday's initial intense flames and the subsequent back-burning.
"Mate, I couldn't control myself," he told AAP on Sunday.
Mr Jones and his wife Eleanor Hajwan-Jones have been returning to their Bell cafe each day to offer free food and drinks to any exhausted firefighters in the area.
"These men and women are fantastic. I can't thank them enough."
Despite the terrifying experience, he said they had no plans to quit.
"This is the Blue Mountains. Tourists will still want to come again here after the fires are gone," he said.
On Sunday evening, fires in Balmoral, Mt Victoria and Springwood, remained at a watch and act alert as more than 60 blazes burned across the state, with just under 20 out of control.
RFS Commissioner Shane Fitzsimmons told reporters that deteriorating weather conditions could spark force evacuations across the Blue Mountains, including in built-up areas such as Leura and Katoomba in the coming days.
Describing the conditions as a "whole new ball game" and in a "league of their own", Mr Fitzsimmons said high winds, temperatures and dropping humidity were set to intensify through Monday, Tuesday and Wednesday..
"We're not talking about emptying out the Blue Mountains," Mr Fitzsimmons said.
"(But) the reality is that these fires are going to pose a significant and widespread risk and threat to communities right across the Blue Mountains."
Meanwhile interstate fire crews, including eight teams from Queensland and two from the ACT, have been deployed to NSW to help with the effort.
Meanwhile forces in New Zealand are also on stand-by to help when needed.
Prime Minister Tony Abbott helped out with backburning efforts in the Bilpin area overnight.