A state-wide total fire ban is in place, and there were 50 fires burning across the state on Tuesday morning - 25 of which were not contained.

Fires since Friday have claimed the lives of three people and destroyed at least 150 homes.

NSW is facing unprecedented dry, hot conditions, described as "horrendous", and a week-long emergency has been declared, as bushfires continue to rage.

Today 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

 Twitter:

NSW RFS

@NSWRFS

Based on the latest forecast, we have mapped where fires on the north coast are likely to spread during tomorrow's dangerous weather. The red shows the predicted spread of fire. Check http://www.rfs.nsw.gov.au/mfu  for detailed information, advice and maps. #nswrfs #nswfires

Smoke from fires in northern NSW is starting to settle in parts of the state including Sydney. People are advised to only call 000 for fires, not smoke. If you need more info on fire danger in your area, call the Bush Fire Information Line on 1800 679 737. #nswrfs #nswfires

Bureau of Meteorology, Australia

@BOM_au

Dry & gusty winds ahead of a trough & cold front will bring dangerous #fire weather conditions to fire-affected areas of #NSW & #Qld from tomorrow. 

A change in wind direction can rapidly alter the course of fires & broaden fire fronts. Stay up to date at: http://ow.ly/aIou50x7gqj

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.

"It's a threat that we haven't faced ever before and I just hope we get through that ok and hopefully we won't have to deal with it again."

All available resources will be thrown at the fires, he added.

"We've got every firefighter we can get, we've got every aircraft we can get, we've got military aircraft coming in to help us to look at rescuing people if people are stuck.

"Absolutely everything we can do is being brought to bear."

Army on standby:

Premier Gladys Berejiklian on Tuesday morning said the dire forecast had not changed and told residents to heed the warnings of authorities and head for safety.

"We need to make sure every community member takes the opportunity to assess the situation and act with precaution in every possible manner," Ms Berejiklian told reporters in Sydney.

"I can't thank enough volunteers and personnel that have been on the ground."

RFS Commissioner Shane Fitzsimmons said fires could spread so quickly in such conditions that people can find themselves in severe danger before help arrives.

"Leaving early and well ahead of any fire in your area is the safest option. Safest options might include going to the local shopping centre, going into town, where you're not in the bushfire-prone area," he told reporters on Tuesday morning.

More than 3,000 firefighters and 60 aircraft are ready to fight the blazes. 

Defence Minister Linda Reynolds has said ADF personnel were not trained firefighters but they would be on standby to provide other support if needed.

Hundreds of schools have been closed for the day, with Education Minister Sarah Mitchell saying "safety remains the number one priority".

Emergency Services Minister David Elliott said residents face what "could be the most dangerous bushfire week this nation has ever seen".

Mr Rogers said places where fires are already raging and are not contained such as the mid-north coast and north coast are "going to cause us problems".

But he added the mission is to "overwhelm" any new fires elsewhere with fire trucks and aircraft so they don't take hold.

More than 100 people have been injured including 20 firefighters hurt trying to protect communities. 

NSW Ambulance Commissioner Dominic Morgan is considering bringing in extra resources from interstate to cope with the demand. 

Climate change dispute:

Recent days have seen a war of words break out over a potential link between the fires and climate change.

NSW Premier Gladys Berejiklian said now is not the time to discuss the issue, but insisted her government has not shied away from talking about it and will discuss it at another time.

Nationals leader Michael McCormack condemned what he described as the "disgraceful, disgusting" behaviour of "raving inner-city lunatics" linking climate change to the blazes.

But some of those living in rural regions who have been directly affected made their feelings clear.

"To disregard the issue of climate change in a situation like this is wrong," Cerene Lowe, whose home was among many razed in Wytaliba on Friday

Fellow Wytabila resident and Glen Innes Severn mayor Carol Sparks, whose home was severely damaged in a blaze, said there was "no doubt" about the link to climate change.

Source | SBS