Sydney - Australia's east coast received its biggest downpours in decades Thursday, confounding efforts to clean up after weekend storms that tore off roofs, downed trees and left thousands of homes without power.

Brisbane, the Queensland state capital, was again in the eye of the storm, with rainfall of up to 250 millimetres prompting thousands of householders to call emergency services for help.

Crews were out in boats, paddling along flooded highways and taking stranded motorists aboard.

"As people clock up the damage this morning, I think we'll get a much clearer picture of how widespread this is," Queensland Premier Anna Blair said.

The biggest storm cell in 30 years swept Sunday over Brisbane, turning night into day and bringing down trees and power lines and damaging hundreds of homes. The Defence Force was called in to help rescue efforts, and some areas were declared disaster zones.

RACQ Insurance chief executive Bradley Heath put the bill of the weekend damage at "hundreds of millions of dollars." (dpa)