Senator Bob Brown made the call after claims that Australia's INTERFET troops introduced the pest to East Timor in 1999.

The Australian Defence Force says vehicles and equipment from a range of organisations have been transported from Australian ports to East Timor, but it would be difficult to pinpoint the source of any introduced species.

Senator Brown says it does not matter exactly who spread the toads, Australia is responsible.

"Whether or not the toads came from Australia to East Timor via the army is very secondary to the fact that it came from Australia and Australia must put every urgent means at the disposal of East Timor to get rid of them," he said.

Senator Brown says the toads pose a serious threat to East Timor's economy and environment, and Australia must act to get rid of them before the wet season.

"This is a massive, difficult, urgent and potentially costly job but the cost of not doing it is astronomical and unthinkable," he said.