Flash floods hit Melbourne

The worst thunderstorm in a century have hit Australia's second largest city, forcing firemen to use boats to rescue people stranded on top of cars and roofs as flash floods raced through large parts of Melbourne.

More than 100 millimetres of rain was recorded in two hours in some suburbs in the early hours of Wednesday.

Severe hail storms damaged cars, uprooted trees and flooded homes. There were no reports of injuries.

"This is a once in 100 year event," Melbourne Weather Bureau forecaster Dean Stewart told reporters.

The Victorian State Emergency Service responded to more than 1,000 calls for assistance.

Under one city bridge, 10 people were forced onto the top of their cars as chest-high water cascaded past their vehicles.

"We've got a lot of flooding, we've got trees coming down and we've got a lot of houses flooded and ceilings collapsed," emergency services officer Danny May said.