Irukandji jellyfish, among the world's most toxic creatures, is spreading along Australia's coastline as a result of global warming reports The Telegraph.

Their discovery has halted production of a Hollywood film "Fool's Gold" starring Kate Hudson and Matthew McConaughey, who were originally due to be filmed swimming in the sea.

The size of a thumbnail and translucent, they are all but impossible to detect in the water, but were thought confined to Australia's northern tropical waters.

Marine biologists have now found them off Queensland's Fraser Island - 400 miles south of their previously assumed range. If they migrate south they could threaten the safety of swimmers, surfers and snorkellers along southern Queensland's Gold Coast and Sunshine Coast regions.