A total fire ban has been declared across the ACT as emergency services face the kind of extreme conditions which created Canberra's devastating 2003 firestorm.
On January 8, 2003, 45km/h winds, gusting at twice that speed, whipped up fires ignited by lightning strikes which had peppered the mountain ranges west of Canberra, as happened on Saturday and Sunday.
Meteorologists are warning Tuesday's weather conditions will create the ''recipe for hot, dry, windy conditions that are conducive to severe fire danger''.
Temperatures could reach up to 38 degrees, while strong north to north- westerly winds of 40km/h gusting up to 60 to 80km/h are predicted.
Australia is likely to have posted a record average maximum on Tuesday, beating the previous high of 40.17 degrees set on December 21, 1976, said Karl Braganza, manager of climate monitoring at the Bureau of Meteorology.
NSW Premier Barry O'Farrell warned Tuesday's soaring temperatures, which will push above 40 degrees, may create the worst fire danger his state has ever faced.
A total NSW-wide fire ban was applied on Monday night while the Shoalhaven and Illawarra area, along with Southern ranges region, are the most at risk, categorised as having catastrophic conditions.
The ACT is facing ''extreme'' conditions, which means a fire could be uncontrollable and unpredictable with fast-moving flames higher than roof tops. Extreme also means a very high likelihood people in a fire's path would be injured or die. Many homes and businesses would be destroyed.
The ACT region experienced a taste of the potential dangers facing firefighters when a fast-moving grass fire just south of Gunning left a firefighter with burns to his face and hands on Monday afternoon.
The fire ripped through over 70 hectares of land near Gundaroo Road, roughly 8 kilometres south of Gunning. The fire damaged a tanker and left a firefighter in Concord Hospital in Sydney with burns.
The NSW Rural Fire Service was able to contain the fire by about 5.20pm. The fire did not threaten any homes.
On Tuesday morning, ACT firefighters expect any one of 1600 lightning strikes in remote areas to spring alight in the high winds which will build from mid-morning.
The biggest of three fires burning since Saturday, at Mount Ginini and covering 26 hectares, is contained but could have hot spots.
The five-hectare Sentry Box Mountain fire near the ACT/NSW border is controlled.
Clusters of small fires at Rendezvous Creek are extinguished.
ACT rural fire service chief Andrew Stark said fires could be smouldering undetected.
''It doesn't matter how many times we look and how carefully our fire tower spotters have their eyes peeled on Monday, it is like blowing the candles on the cake, until you put air onto it. We won't know they are actually there.'' In steep areas firefighters could not roll over every log and check it. Smouldering logs were deluged with loads of water from helicopters.
An emergency control centre encompassing ACT government directorates and emergency services has been established at the ESA's Fairbairn headquarters.
"We will have representatives from Actew, Education, water, power and all different elements of government in here to make sure we get the information out to the community and we can maintain all those support services,'' Mr Stark said.
By late Monday the risk in the mountains had eased, but will change in higher winds.
''We need the community to be aware that we could see very active fire in the Brindabella Ranges that we probably haven't seen since the 2003 fires,'' Mr Stark said.
With the north and east of Canberra facing ''catastrophic'' fire conditions, Mr Stark said: ''If we get those [catastrophic] winds moving further south than forecast then that would be a very dangerous fire condition, very quickly.''
Bureau of Meteorology duty forecaster Kenn Batt warned that strong wind gusts were likely to be experienced for much of the day, easing late in the afternoon.
''[Tuesday] is shaping up, that if there was a fire around, it would run, run hard, and be very difficult to control in those winds," Mr Batt said.
A decade ago substantial fires burned on both sides of the ACT/ NSW border.
In the formative stages of the Canberra firestorm crews were withdrawn overnight because of the heightened risk, which drew strong criticism from a subsequent ACT coronial inquest.
On Saturday night crews were winched out by helicopter from the most remote fire at Sentry Box Mountain.
Mr Stark said : ''It comes down to how fast we can get people out if it changes. That fire was allowed to burn. They worked on the flank which represented the main risk, and it had not progressed much more (on Sunday) morning.''
Unlike a decade ago, a D4 bulldozer and a D6 were quickly deployed on an upgraded road to Mount Ginini car park, and crews with hand tools and hoses remained overnight on Sunday.
On Monday four tankers and a commander remained overnight.
Bulldozers stopped work about 9pm and began at 5am on Monday.
Hot spots remain within containment areas, but are not burning freely.
In steep country, a burning tree could roll for 100-200m into unburnt country.
"We've got all our vehicles right across ACT Rural Fire Service, which includes the volunteer brigades, and the parks brigade, together with all the bushfire appliances," he said.
"The other appliances at ACT Fire and Rescue will all be manned and available right through the day for a response straight into the ACT, but also to our near neighbours surrounding if things develop quickly."
Emergency Services Minister Simon Corbell said he was in regular contact with the ESA, and was confident his directorate was "taking all necessary steps to be prepared to respond to any incident".
"The key message to Canberrans is that this is a very dangerous weather day," he said.
"If a fire does start, it's going to develop very quickly and it will be very difficult for emergency services to control.
"I would urge Canberrans who are in vulnerable locations, particularly adjacent to bushland or the urban interface, to revise their bushfire plan to decide whether they will stay and defend their property or move to a safer location should a fire occur."
Mapping has much improved since 2003, when firefighters were confused by outdated information, and hampered by jammed radio channels.
''There is the investment we have made in mapping but there is also steps that have come alng with internet and electronic mapping,'' Mr Stark said.
''The aerial photos and quality we have now, on my own I can zoom in and get a sense of exactly where the crews are working. Mapping technology worldwide has come ahead in leaps and bounds.''
He said the Territory Radio Network had full coverage.