Flooding rains are set to continue lashing the Australian east coast even though it avoided its first tropical cyclone in 51 years.

The slow-moving tropical storm, named Alfred, is on track to bring dangerous winds and flooding along the coast of Queensland and New South Wales, including Brisbane.

Ex-Cyclone Alfred stalled off the rain- and wind-lashed coast of eastern Australia on Saturday, threatening to unleash floods after blacking out more than 330,000 homes and businesses.

Tropical cyclone Alfred is a reminder that powerful storms have the power to show up in some surprising places.