SYDNEY (BLOOMBERG) - Australia is in the grip of another heatwave with temperatures forecast to soar over the weekend, exacerbating deadly wildfires that have ravaged the nation for months.

Severe heat will spread across the south-east of the country over the next few days, building to "extreme" conditions in some areas, according to the Bureau of Meteorology. Parts of western Sydney are expected to reach 45 deg C by New Year's Eve.

The intense weather could worsen blazes that have already burnt out more than 6 million acres (2.4 million hectares) of forest and bush land - and area larger than New Jersey - since the wildfire season began unusually early in winter amid widespread drought.

Nine people have been killed and more than 950 properties destroyed, triggering a debate about the impact of global warming in the world's driest-inhabited continent.

The crisis has turned the spotlight on Prime Minister Scott Morrison's conservative government, which champions the coal industry and has dismissed calls to take more steps to curb emissions.

Mr Morrison cut short a pre-Christmas family holiday to Hawaii amid a public backlash against the unannounced trip.

Australia's New South Wales state, the most populous, has borne the brunt of the fires. A giant blaze north-west of Sydney, known as the Gospers Mountain fire, has destroyed more than 1.2 million acres - an area about seven times the size of Singapore.

Another massive blaze, the Currowan fire, has played havoc with holidaymakers along the coast south of Sydney, threatening tourist towns and forcing the authorities to intermittently close the main highway.

The fire stretches about 96.5km from Nowra to the resort town of Batemans Bay and has destroyed about 530,000 acres.

About 1,300 firefighters are in the field across the state, battling about 70 blazes, according to the Rural Fire Service.

The states of Queensland, Victoria, Western Australia and South Australia have also been hit, stretching the resources of fire services, which are mainly staffed by unpaid volunteers.

The bush fires have already pumped out more than half of the country's annual carbon dioxide emissions, and left cities including Sydney and Canberra frequently shrouded in a toxic haze of smoke.

With temperatures forecast to reached 40 deg C in Adelaide on Monday (Dec 30), the state government in South Australia has declared a "code red" under which the authorities will provide additional support, including food and shelter, to vulnerable homeless people.