Researchers at a far north Queensland university say the key to trapping toads could lie in a seductive mating call.

Professor Ross Alford from James Cook University in Cairns says they are working on a solar-powered trap that plays recordings of toad calls.

He says they have found both female and male toads can't resist a deep, throaty call.

"We are working now on whether it might actually be possible to artificially engineer a mating call that will work better than a normal toad call," he said.

"It is actually possible to make a super-attractive call.

"Females are often more attracted to calls that suggest it will be a large, powerful male."

Cane toads are introduced pests in Queensland, northern New South Wales and the Northern Territory, and are now encroaching on the top end of Western Australia.

According to the Territory Natural Resources Department, the toads now populate 500,000 square kilometres of the Australian mainland.

Natives of central and South America, about 3000 cane toads (bufo marinus) were imported to Australia in 1935 to control pest beetles in sugar cane plantations in Queensland.

They arrived in Darwin in the wet season of 2004-2005.