The NSW Rural Fire Service has been handed special authority ahead of catastrophic fire conditions expected for the Hunter Region and Sydney on Tuesday.
NSW Premier Gladys Berejiklian announced a state of emergency on Monday for the next seven days.
It came as emergency crews braced for worsening conditions across the eastern part of the state, after bush fires devastated communities on the Mid North Coast and northern NSW in recent days.
Ms Berejiklian described Tuesday's predicted fire conditions as "unprecedented".
"Our state has already been hit by some of the most devastating bush fires we have ever seen, with three lives lost and more than 150 structures destroyed," she said.
"With catastrophic weather conditions predicted for this week, particularly Tuesday with hot weather and strong winds, I have decided to take the commissioner's advice and make this declaration.
"It will ensure our state is best placed to respond to the predicted fire conditions."
It is the first state of emergency declared in NSW in six years.
Read more: Twenty firefighters injured as NSW burns
The special powers give RFS commissioner Shane Fitzsimmons the authority to direct any government agency in their duties, control and coordinate government resources, conduct evacuations, close roads, pull down and shore-up infrastructure at risk of collapse, enter or take possession of properties as part of the emergency response and order the shutdown of electricity, gas, oil and water utilities.
RFS announced on Sunday afternoon a catastrophic fire danger rating - the highest on the scale - would be in place for the Hunter and Greater Sydney on Tuesday, with hot, windy and dry conditions predicted.
"Homes are not designed to withstand a fire under these conditions," RFS said in a statement.
"If a fire starts and takes hold during catastrophic fire danger conditions, lives and homes will be at risk."
Read more: NSW village endures 'apocalyptic' fire
A 309 hectare bush fire at Awaba remained at advice level on Monday morning, as dozens of blazes continued to burn across eastern NSW, between Forster and Casino.
A top of 37 degrees is predicted for Newcastle and much of the Hunter Region on Tuesday, with Singleton forecast to reach a top of 38 degrees.
Mr Fitzsimmons told reporters in Sydney on Monday morning the safest thing to do during catastrophic fire conditions was "not be in an at-risk area".
"Tomorrow we are facing some horrendous conditions," he said.
"If fires start and take hold they can be burning and impacting on people's homes, people's property, before we even get a triple zero call, let alone getting a fire appliance or an aircraft to start dealing with that fire.
"The risk is absolutely real."
Lake Macquarie City Council has closed several reserves and pathways in the local government area because of the impending conditions.
Mount Sugarloaf and the Sugarloaf State Conservation Area, the Fernleigh Track, Green Point Foreshore Reserve will be closed until 5pm on Wednesday.
The council said all Landcare sites are also closed.
NSW National Parks and Wildlife Service closed all parks and reserves "including tracks, trails, campgrounds and picnic areas across the Central Coast, Hunter, Mid North Coast, North Coast and North West of the State" from Monday until further notice.
RFS Releases Standard Emergency Warning - 1pm, November 11
This is a warning from the New South Wales Rural Fire Service.
Catastrophic fire danger is forecast for the Greater Sydney, Greater Hunter and the Illawarra Shoalhaven areas tomorrow, Tuesday.
Catastrophic is the highest level of bush fire danger.
If you are in the path of a fire in these conditions, your life will be at risk.
Avoid bushland areas.
Safer locations may include large centres, such as towns or cities well away from bushland areas.
If you are unable to leave, identify a safer location in case a fire starts. This may include a Neighbourhood Safer Place.
Stay up to date on bush fires in your area by listening to local radio, through the RFS website, through social media and the Fires Near Me NSW app.
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