SYDNEY - EASTERN Australia was battered by wild weather Friday, with the south facing extreme heat and the worst wildfire conditions in 25 years while floods ravaged the north.

A once-in-a-century heatwave was forecast to intensify over the weekend, with temperatures soaring to well above 40 deg C and high, dry winds across four states, authorities said.

'We're talking about fire danger that hasn't been seen since Ash Wednesday coming up on Saturday,' said Ron Patterson, an environment department spokesman from Victoria state.

The Ash Wednesday fires of 1983 killed 75 people and devastated large areas of Australia's south-east.

The mercury is expected to top 44 deg C in Sydney, Australia's largest city, on Sunday, with temperatures in excess of 46 deg C forecast for inland areas.

Much of the south-east has sweltered under record temperatures this summer, with wildfires destroying at least 29 homes last week and dozens of mainly elderly people dying of heat-related stress.

But in the north-east, floodwaters have devastated more than one million sq km, inundating homes, destroying at least a fifth of the region's sugar cane fields and stranding tens of thousands of cattle.

'There are cattle suffering pretty seriously,' said Cattle Council of Australia president Greg Brown.

'There is some mortality rate, just how great that is at this stage is pretty hard to tell, but it's going to be, I think, substantial.' Farmers unable to move produce due to the floods were facing millions of dollars in losses, while the army was preparing to drop food into some towns that have been cut off for up to a week.

The deluge, which followed two recent cyclones, hit almost 3,000 homes, forcing dozens of evacuations and leaving scores of people stranded.

Further rains are expected, as a tropical low hovers off the coast, the weather bureau said. -- AFP