By Phil Mercer
BBC News, Darwin
Officials in Western Australia have called for the army to be deployed to stop an invasion of cane toads.
The toxic toads have wrought havoc on indigenous animals
The toxic amphibians have spread in plague-like numbers across tropical Australia since being introduced to the country in the 1930s.
They were first brought to Australia from Hawaii to eradicate cane beetles, but they have had a devastating impact on native wildlife.
There could be as many as 100 million cane toads in tropical Australia.
March of the toad
The toads have reached the outskirts of Darwin in the Northern Territory.
Over the border, officials in Western Australia are watching very nervously.
They want the army to intercept these poisonous pests as their advance continues.
The state government has written to its federal counterpart in Canberra, asking for permission to use troops as a first line of defence.
Much of Western Australia's interior is inhospitable and inaccessible.
In such a remote area, the resources of the military could be invaluable.
Cane toads are big, warty creatures and have had a devastating effect on Australian wildlife.
They carry a venom so powerful it can kill crocodiles, snakes and other predators in minutes.
All attempts to fight the spread of the cane toad have so far failed.
No-one is quite sure of the most effective way to stop them.
One member of Australia's federal parliament has previously suggested that people should beat them with a golf club or a cricket bat.
Animal welfare groups have said that the humane way to get rid of these invaders is to put them into a freezer until they die.