NSW is facing unprecedented dry, hot conditions, described as "horrendous", and a week-long emergency has been declared, as bushfires continue to rage.
NSW is bracing for catastrophic and unprecedented conditions in what could be the most dangerous bushfire day in Australia's history.
As dozens of fires continue to burn across the state, temperatures in the high 30s, low humidity and winds of up to 80 kilometres per hour are forecast for Tuesday.
The state is facing a threat it has never seen before, Rural Fire Service Deputy Commissioner Rob Rogers said, adding: "I just hope we get through that OK."
A catastrophic fire danger rating - the highest possible level - is in place for the Greater Sydney, Greater Hunter and Illawarra Shoalhaven areas, covering about 6 million residents.
A week-long state of emergency has been declared.
"We've just got town after town after town that will be under threat," Mr Rogers told ABC News on Monday night.
Smoke from more than 50 fires burning in northern NSW has covered Sydney with clouds of smoke even reaching as far away as New Zealand.
NSW Health warned people in Sydney and the Hunter to take precautions with smoke blowing south from fires on the state's mid-north coast causing poor air quality from Monday afternoon.
