Arsonists are exacting their toll as Australia's bushfire crisis again deepens, with temperatures to soar to the low-40s in many eastern regions and no relief expected until at least next week.
Despite special police task forces, surveillance of known arsonists and warnings of penalties as severe as 25 years' jail, youths have been arrested after allegedly setting fires in tinder-dry grassland.
Other outbreaks, including fires that consumed hundreds of hectares, are being investigated as possible arson. Heavy fines have also been imposed on people ignoring total fire bans or starting outbreaks with sparks from tools such as angle grinders.
New South Wales Rural Fire Service Deputy Commissioner Bob Rogers warned of the potential consequences of arson as firefighters battle against about 100 firestorms, 18 of them still to be contained late yesterday.
"There are enough fires that start from either accidental or natural causes without dealing with fires that are started by morons who think it's a big joke to light fires in the bush," he said.
NSW Acting Police Commissioner Nick Kaldas said arsonists would be tracked down and punished.
"One fire deliberately lit is one too many and I can't condemn that strongly enough," he said.
"Something like that might be fun for a minute but at the end of the day it could result in people dying."
As the eastern states headed towards the crisis that has so far destroyed more than 100 homes, devastated grazing and cropland, killed thousands of head of stock and raged through forests and national parks, police began targeting known arsonists.
They were warned they would be watched and prevented from lighting fires.
The threat is well established with previous major fires - some causing death and huge property losses - started by arsonists.
The Australian Institute of Criminology estimates that up to half the 54,000 bushfires that erupt every summer across the continent are deliberately lit or start in suspicious circumstances. The annual costs run to A$1.6 billion ($2 billion).
Governments have responded with heavy penalties that range from 10 to 25 years' jail. If people die in a fire, convicted arsonists face life terms for murder or manslaughter.
A tough line is also taken against others who set campfires, carelessly start hazard reduction burning or shower sparks from agricultural or welding equipment, which can cause catastrophic firestorms.
The message is still failing to get through to some.
Two 16-year-old youths were arrested after nine fires were started in bushland near Sydney's Macquarie Fields, overnight on Thursday, three others appeared in court after fires in the western suburb of Shalvey, and three more were arrested in Newcastle.
Police are also investigating a suspicious fire at Lithgow, in the Blue Mountains, and another near Windsor, northeast of Sydney.
Police further separately charged two men after fires were lit during the total fire ban, and a 76-year-old Mudgee man was accused of sparking a large grassfire in Mudgee, in the Hunter Valley.
Meanwhile, NSW firefighters were late yesterday battling about 100 fires, including major outbreaks near Cooma, in the Snowy Mountains - Arsonists add to disaster
The fires are visible from the the International Space Station.Picture / AP
now raging out of control for days - at Yass, near Canberra, and Sussex Inlet on the state's South Coast.
The Yass fire has a diameter of 94km.
Residents have been warned to prepare for the worst.
Another fire at Deans Gap near Nowra on the South Coast has become more complex as flames near a former practice bombing range in Morton National Park littered with unexploded weapons.
The Rural Fire Services' Brett Loughlin told ABC radio that firefighters could not battle the blaze if it broke through to the former range.
"We can't do any water-bombing with aircraft or something like that in case the weight of the water when it hits the ground sets off any unexploded ordnance," he said.
"So it's a total no-fly zone and that will mean [if] the fire gets into that area, there's nothing we can do for it except wait for it on the other side."
In Victoria, a new outbreak northeast of the Goldfields city of Ballarat erupted late yesterday, although most other outbreaks had been contained during the cool respite of the past days.
The Bureau of Meteorology said soaring temperatures and strong, hot winds would continue until early next week, extending the crisis.