As if bushfires, drought and floods aren't enough, Australians have now been warned about a volcanic eruption.

A scientist says an eruption is "well overdue" and there are hundreds of volcanoes that could cause trouble, from South Australia and Victoria through to Queensland.

Melbourne geologist Bernie Joyce wants "eruption response plans" drawn up.

He says there are 400 volcanoes in Victoria and South Australia, and almost as many in Queensland.

"A significant eruption seems well overdue," said Professor Joyce, who has been associated with the University of Melbourne.