Michael Coughlan, head of the Australian Bureau of Meteorology's National Climate Centre, said he was cautiously optimistic of a better chance of autumn rain after scientific data suggested weather patterns were returning to normal.

"We will see some sort of a break in the autumn period," he told the Australian Broadcasting Corporation.

During an El Nino pattern the Tasman Sea, between Australia and New Zealand, cools so easterly winds carry less moisture than normal, meaning lower rainfall across Australia's East coast, the area worst hit by the current "Big Dry".

Signs of a reprieve included changing sub-surface temperatures in the Pacific, and trade winds strengthening to near-normal values over the past month, the Bureau of Meteorology said.

In addition, the Southern Oscillation Index, which is markedly negative during an El Nino pattern, had moved back towards postive territory, it said.

Poor rainfall has drastically reduced Australia's agricultural output, and left dams in many of the nation's cities dangerously depleted.

"Now whether or not it's a big enough break to recharge those very empty water storages, that remains to be seen," Coughlan said.

He said it would probably take until March for a definitive picture to emerge, and cautioned that after the last El Nino ended in 2003, rainfall was still lower than normal.

The new data backs up a similar prediction made in recent weeks by commercial meteorological prediction service Weatherzone, which foresaw an end to the El Nino-driven drought.

Weatherzone's Matt Pearce said the El Nino effect -- which resulted in the third-lowest rainfall on record nationwide for the August to November period -- had its greatest influence on Australia's weather during spring, with a decreasing impact in summer.

"Therefore, we expect rainfall to gradually return to more normal levels over the next few months."

Even so, temperatures would likely remain well above average across most of Australia through summer and into early autumn, Pearce said.

He said El Nino conditions had also been the major factor behind the bushfires that ravaged at least 850,000 hectares (2.13 million acres) across Australia before cooler Chistmas weather granted exhausted firefighters relief.