SYDNEY • A record amount of single-day rainfall for the month of May has caused major flash flooding in the Australian city of Hobart yesterday, with the authorities ordering mass evacuations as roads turned into rivers.

Tasmanian Bureau of Meteorology forecaster Matthew Thomas said the 129mm of rainfall made it the wettest single day since 1960 and the fourth highest recorded.

"We had a low-pressure system with a trough extending into Hobart and with that came thunderstorms that were very stationary," Mr Thomas explained.

As a result, cars floated down city streets as the deluge wreaked havoc on the usually tranquil city.

Over 14,000 homes were left without power and several local television stations, including the ABC, SBS and WIN, went off air after a lightning strike knocked out transmission at Mount Wellington.

Across the rest of Tasmania's capital and its surrounding areas, 100kmh winds tore roofs off houses and upended trees, resulting in at least 280 emergency calls.

So far no casualties have been reported. However, the authorities urge caution as more bad weather is forecast later in the day.

XINHUA