MELBOURNE (REUTERS, AFP) - Bush fires near the Australian capital Canberra forced the city's airport to close on Thursday (Jan 23), as passenger flights were halted to make way for aircraft working to extinguish the blazes, authorities said.

High temperatures and strong winds fuelled an outbreak of new blazes across several areas in eastern Australia on Thursday, ending a period of respite following several days of rains and cooler weather.

Since September, hundreds of wildfires in Australia have killed 29 people as well as an estimated 1 billion native animals, while incinerating 2,500 homes and a total area of bushland one-third the size of Germany.

Flights to and from Australia's capital were suspended around midday (9am Singapore) Thursday "to allow for aviation firefighting operations", a Canberra Airport spokesman told AFP.

It was unclear how long services would be impacted but the terminal has not been evacuated, she said.

The Australian Capital Territory Emergency Services Agency said the airport had been closed "due to current conditions".

An out-of-control blaze burning south of the airport was upgraded to an emergency level just before midday, with the agency advising residents it was "too late to leave" three suburbs in the path of the fire.

"The fire may pose a threat to all lives directly in its path," the agency said in a warning.

"People in these suburbs are in danger and need to seek immediate shelter as the fire approaches." The fire has so far burned through more than 140 hectares (350 acres), while a second out-of-control blaze has flared to the west of the airport.

Though the airport has been used in aerial firefighting efforts for several months, it was the first time operations had been suspended.

Soaring temperatures stoked the simmering bush fires in the south-east on Thursday (Jan 23), with Sydney forecast to hit 41 deg C.

A fire in the Snowy Mountains region and one in the Bega Valley on the south coast of New South Wales (NSW) state both flared up, with emergency authorities warning residents to get out if they did not plan to defend their properties.

"Fire dangers are just starting to peak, and we're in for a long afternoon and night across many areas of NSW," the state's Rural Fire Service said on its Twitter account.

The Bureau of Meteorology warned that "damaging winds" were driving up fire dangers in some regions, while the country's biggest city was again forecast to wallow in hazardous air quality levels under smoke palls from some 90 blazes burning across the state.

Since September, hundreds of wildfires in Australia have killed 29 people as well as an estimated 1 billion native animals, while incinerating 2,500 homes and a total area of bushland one-third the size of Germany.

The disaster hit the Christmas and summer holiday season, emptying out caravan parks and hotels, devastating peak earnings for businesses dependent on domestic and foreign tourists.

The Australian Tourism Industry Council estimated the immediate loss of revenue at A$2 billion (S$1.9 billion), including forward sales and the physical damage to tourism facilities across regions ravaged by bush fires.

"Whatever the numbers ultimately land at, it's had a significant impact," said Simon Westaway, executive director of the council, which represents small and medium-sized tourism businesses.

Cancellation rates hit 100 per cent in fire-affected areas while tourist facilities even in areas not affected by fires were hit with cancellation rates of around 60 per cent, and there is evidence of international booking cancellations too, he said.

"People see a state of emergency and don't know if they'll be able to get in or out," Westaway told Reuters. "This contagion has really swept across the industry."

Here are today's key events in the bush fire crisis:

*NSW firefighters were tackling 90 fires, with one in the Snowy Mountains area and one on the south coast in Bega Valley at emergency warning levels. In Victoria state there were 17 blazes, with one of those, in the state's north-east, at the "watch and act" warning level.

* Sydney was set for a hot and windy day, with a high temperature of 41 deg C, while the capital Canberra was forecast to hit 33 deg C, facing windy conditions and dust haze, the Bureau of Meteorology said.

* Heavy rain in Melbourne dumped dust fanned up by heavy winds into the Yarra River. However, air quality in the city was rated "good" as the rain doused haze that had affected players at the Australian Open tennis tournament. Last week, a player collapsed in a coughing fit from bush fire smoke during qualifying rounds.

* The Victorian state government on Thursday said it would spend A$17.5 million immediately to save wildlife hit by the bush fires. It planned to focus on species most at risk, including the brush-tailed rock wallaby, the state's most endangered mammal, and the long-footed potaroo and large brown tree frog.

* Economists have estimated the cost of the bush fires to Australia's A$1.95 trillion economy could be as high as A$5 billion. That would shave around 0.25 points off gross domestic product in the December and March quarters, a development that could prompt the country's central bank to cut rates as early as February and lower its growth projections.

* United Airlines Chief Commercial Officer Andrew Nocella on Wednesday said the airline was watching routes in Australia very carefully. "The wildfires really had some impact on demand, so we'll keep a close eye on that," he told analysts on an earnings call.

* A Reuters analysis shows that Australian animals living in specific habitats, such as mountain lizards, leaf-tailed geckos and pear-shaped frogs, are battling the threat of extinction after fierce bush fires razed large areas of their homes.