Hundreds of thousands of people are under a blackout in Queensland, while flood warnings remain in place across New South Wales, after ex-Cyclone Alfred left a trail of destruction along Australia’s east coast.

Fallen trees across the region have already damaged power lines, homes and cars, while the Gold Coast's renowned beaches have become steep sandy cliffs after days of relentless erosion.

Residents are stacking sandbags to protect low-lying properties ahead of a tropical cyclone that is forecast to become the first in 51 years to hit the Australian east coast near Brisbane, the nation’s third-most populous city.