UPDATED 11.55PM

Almost every aspect of modern life will be impacted as ravaged NSW braces for a day emergency officials warn could well see a catastrophic ordeal by fire.

Around 600 schools will be closed across NSW as fire conditions threaten highly-populated areas around Sydney, Wollongong and Newcastle.

Childcare centres in high-risk areas will also close, with parents being urged to contact centres directly for more information. Some TAFE campuses will also shut for the day.

Early on Monday, Premier Gladys Berejiklian declared a state of emergency for NSW for the next seven days.

The NSW Rural Fire Service (RFS) warned that firefighters will not be able to reach many people in emergency situations if a fire takes hold.

“Under these conditions, some fires may start and spread so quickly there is little time for a warning, so do not wait and see,” an RFS statement said.

“There are simply not enough fire trucks for every house. If you call for help, you may not get it.

“Do not expect a fire truck. Do not expect a knock on the door. Do not expect a phone call.”

NSW Premier Gladys Berejiklian has declared a seven-day state of emergency ahead of a “catastrophic” forecast for Tuesday, while Queenslanders have been warned their lives could also be at risk.

The most dangerous fire weather was predicted for greater Sydney and the Hunter Valley. That list was expanded on Monday afternoon to include the Illawarra and Shoalhaven district.

About 60 fires were burning across NSW during the afternoon, 40 of which were out-of-control. About 970,000 hectares of land had been razed – almost as much as the past three fire seasons, combined.

Meanwhile, a bushfire burning on South Australia’s lower Eyre Peninsula thrteatened lives and property, with authorities warning locals it is too late to leave.

The blaze at Duck Ponds burned uncontrolled in stubble  as it rolled towards Port Lincoln before firefighters got on top of the blaze and warnings were downgraded late on Monday night..

• Read more: Fire victims speak out, call for climate awareness

A state of emergency was also in place for 42 local government areas of Queensland, where 51 fires were burning – three of which were considered a major concern.

There was no mincing words from authorities: They wanted residents to be very clear that lives were in danger.

Emergency Services Minister David Elliott warned residents:

[This] could be the most dangerous bushfire week this nation has ever seen.’’

The NSW fires have claimed three lives and so far destroyed more than 150 homes. On top of that, more than 100 people have been injured including 20 firefighters.

More than 350 schools and TAFE campuses will be closed in Sydney, the Hunter region, Blue Mountains and the south coast on Tuesday due to the forecast danger. See a full list of the 367 sites that will be closed here.

A burnt-out car, cabin and sheds owned by Thorsten Kels at Lake Cooroibah Road, Noosa, after the fires on Monday. Photo: AAP

NSW Ambulance Commissioner Dominic Morgan was considering bringing in extra resources from interstate, with plans underway already to deploy another 30 ambulance crews. 

“Over the last few days our doctors and paramedics have been exceedingly busy – they’ve treated over 100 patients for fire-related activity,” Mr Morgan told reporters in Sydney on Monday.

He paid tribute to firefighters injured in the line of duty.

“That’s something that we should all be recognising,” he said.

“Up to 20 (of the people treated) have been directly related to firefighters being injured while protecting their own communities.

Resident Brian Williams returns to survey the damage to his resort in Noosa, QLD, on Monday. Photo: AAP

In Queensland, eight homes had been destroyed near Yeppoon and another was lost on the Sunshine coast.

On Monday, Ms Berejiklian also warned people “for heaven’s sake stay away from bushland” on Tuesday.

Lyn and Peter Iverson with their burnt out office and shed on their property at Koorainghat, NSW, on Monday. Photo: AAP

“The catastrophic weather conditions mean that things can change very quickly,” she said.

“You might think you’re OK and a few minutes later you won’t be. Please heed all the messages you receive. Tomorrow (Tuesday) is not the day to be complacent.”

Even away from fire zones, communities are expected to be impacted by smoke that can be particularly harmful for children, the elderly and anyone with asthma or other breathing conditions.

The fire danger tomorrow is now expected to be worse than originally forecast. The Illawarra/Shoalhaven is now forecast to experience a Catastrophic fire danger, as will Greater Sydney and Greater Hunter. More info here: https://t.co/RQyA5UAi8x #nswrfs #nswfires pic.twitter.com/1xlwByvpMz

— NSW RFS (@NSWRFS) November 11, 2019

The NSW RFS said there was also serious danger for people living outside the regions that had been warned of catastrophic danger.

“There is a risk in all bushland areas, stretching from Bega all the way to Byron, from the Victorian border to the Queensland border,” an RFS spokesman said in a media alert.

“Across all fire grounds now we have more than 970,000 hectares that has been burnt or is burning. That is a massive area almost more than the last three fire seasons combined.”

Thomas Eveans inspects the remains of his house which was destroyed by a bushfire in Torrington, near Glen Innes, NSW. Photo: AAP

Mr Elliott said the week-long state of emergency for NSW was precautionary but necessary.

“We have tools like state of emergency available to us to ensure there is no legal barrier, there are no operational barriers, to ensure that the people of the Rural Fire Service (can) do what they’re meant to do,” the minister said.

“Catastrophic is off the conventional scale,” RFS Commissioner Shane Fitzsimmons said.

“We are talking about indices that go well beyond the old scale of 100.”

The risk for Queensland is also expected to escalate from late Tuesday and into Wednesday, when strong winds and higher temperatures return.

Premier Annastacia Palaszczuk said Queenslanders must be prepared to leave their homes if authorities told them to.

“Don’t second-guess them, just do it because it’s in the best interests of you and your family. We want people to be safe,” she told ABC television on Monday.

Heavy smoke haze is blanketing the state’s south-east, where respiratory issues are a concern and people have been warned to stay indoors.

-with AAP