Police are combing through hundreds of reports on several bushfires across NSW which might be suspicious and have warned they will put anyone responsible before the courts.
Two men have been charged with possessing RFS equipment, with one reportedly seen in the Royal National Park dressed as a firefighter.
"We're going to do everything in our power to establish whether fires were suspicious, whether they were deliberately lit and we're going to put people before a court," NSW Police Acting Assistant Commissioner Stuart Smith told reporters in Parramatta.
He said there are "several" fires from Lake Illawarra to Oxley for which police are working to determine the cause.
Authorities are also looking into several suspicious fires in Sydney's South Turramurra, at Loftus in the Royal National Park, at Katoomba in the Blue Mountains, at Wollongong's Berkeley and at Moonbi near Tamworth.
Police officers were seen on Tuesday searching a car and speaking to two young males at Canoon Road in Turramurra.
Mr Smith said police had spoken to a number of individuals in relation to fires and praised the "fantastic" work by members of the community who had come forward with information.
He said it was "an extremely irresponsible act by any individual to light a fire yesterday" as parts of the state faced "catastrophic" conditions.
NSW Emergency Services Minister David Elliott said people "must have arrived from Mars in a bubble" to not know about total fire bans in the state after nine alleged breaches.
A 19-year-old man was arrested at Loftus on Tuesday night, following reports a man dressed as a firefighter was seen riding a scooter in the Royal National Park.
He was charged with impersonating an emergency services officer and having goods in custody suspected of being stolen.
He is due to appear in court in December.
A 36-year-old man was charged after RFS-branded equipment was allegedly found at a property in Koonorigan. He was due to appear in court on Wednesday.
Meanwhile eight men allegedly breached NSW's total fire ban this week while a nine-year-old boy admitted to lighting a fire with a blowtorch.
NSW Police allege the first incident saw a 27-year-old man light a campfire at Wallacia in Sydney's west on Monday and he was fined $2200.
A 35-year-old Prestons man also allegedly burned fence palings in a cylindrical barbecue, causing a fire, while a third man allegedly lit a coal barbecue at a Lalor Park home in Sydney's west on Tuesday.
An additional five men were on Wednesday found to have breached the ban by lighting barbecues and incinerating rubbish. One man allegedly resisted arrest when he was found lighting candles at a Campbelltown campsite.
The nine-year-old, due to his age, was warned under the Young Offenders Act after a grass fire broke out in Nowra on Tuesday. Police said the boy, in a group of other children, admitted to lighting the fire with a blowtorch.
The statewide fire ban has been extended into Wednesday.
It means people cannot light, maintain or use a fire in the open, or carry out any activity in the open that causes, or is likely to cause, a fire.