CANBERRA Firefighters braced for another day of dangerously hot and windy weather after bushfires claimed three lives, left 150 injured and destroyed almost 400 homes in Canberra's worst disaster.

Thousands of people were forced to flee as the fires engulfed the national capital with horrific speed on three fronts, completely overwhelming an inadequate brigade of 450 firefighters.

Many crews found themselves fighting to save their own lives, with at least four fire trucks and one complete fire station reportedly destroyed.

The entire city was blanketed in thick, black, choking smoke and flying embers, roads were closed as power blackouts created traffic chaos and electricity supplies to much of the capital were cut.

Firefighting helicopters, an essential tool to crews fighting the fires which struck Sydney several times during the worst bushfire season for decades, were unable to take off because of smoke over Canberra.

Blackest day

Hundreds of fresh firefighters were drafted into the Australian Capital Territory (ACT) from neighbouring New South Wales state to prepare for a second day of firestorms after what is being labelled Canberra's blackest day.

The ACT emergency services bureau (ESB) said fire crews and emergency workers were mopping up on Sunday morning and preparing fire breaks around suburbs considered most at risk ahead of a wind change later in the day.

Fires were still burning out of control in two northern suburbs.

It was Canberra's southern, western and northwestern suburbs which bore the brunt of the fires on Saturday and overnight, with at least 388 homes confirmed destroyed and the number expected to grow.

ESB spokesman Kelvin Watt said about 2,500 people had been evacuated and residents were advised not to return to their homes as emergency crews took in bulldozers to create fire breaks.

Without power

"They are just trying to get prepared for this afternoon's onslaught," he said.

A change of winds from the north and northwest Sunday afternoon was expected to put more suburbs in Canberra's northwest in the front line of the fires.

The two people who were confirmed dead were a 61-year-old man who died of smoke inhalation while trying to save his family home, and a 83-year-old woman.

Watt said 25 percent of Canberra remained without power and at least two western suburbs were without water as the pump at the local water tank had been destroyed.

PM at scene

Prime Minister John Howard interrupted his holidays to fly to Canberra from his Sydney residence to visit the fire control centre and to speak to some of the residents who poured into evacuation centres overnight.

More than 50 people were treated for fire-related injuries at the local hospital, while two women suffering severe burns were evacuated from Canberra to Sydney for treatment.

ACT chief minister John Stanhope said the fires were the worst crisis the city had ever had to face.

"What we've experienced today, I would imagine, is a once in a 100 years or a 200 years experience," Stanhope told reporters Saturday.

"It's a fire, a firestorm and an emergency of a sort that I don't think any of us would have imagined, see or experience here in Canberra.

"It is a day of enormous sadness." AFP