Sydney, Nov 28 (IANS): Over 500 Australians called for emergency assistance in just two hours after storms lashed Sydney and nearby regions, equalling rainfall of its monthly average in that time, causing floods, power cuts and flight delays on Wednesday, Met said.

Australia's Bureau of Meteorology said it was the region's wettest November day since 1984. "The intensity of that rainfall was phenomenal -- 91mm fell in 90 minutes," forecaster Rob Taggart told the Australian Broadcasting Corporation.

Authorities said at least 11 people were rescued from vehicles trapped in floods. One man died in a car accident. Images posted online showed flooded roads, houses and train stations, the BBC reported.

Authorities urged people to stay safe ahead of more forecast storms later on Wednesday.

"We cannot stress enough... motorists should never attempt to drive through flood waters or cross flooded causeways," said Assistant Commissioner Michael Corboy of NSW Police.

Firefighters had to negotiate flooded roads while responding to an alarm in Artarmon earlier in the day. "Take care if you're travelling today and don't enter floodwater," Fire and Rescue Department of New South Wales tweeted. It said: "If it's flooded, forget it!"

Two police officers were injured here after being hit by a falling tree while trying to help motorists, an official said.

The weather played havoc with the morning commute in Australia's biggest city here, with many transport services cancelling or delaying, including more than 50 flights, the BBC said.

The storm was centred on coastal parts of New South Wales, but was reported to have missed many inland regions that were affected by drought.