Stephen Spencer, Canberra – Foreign Minister Alexander Downer today lashed out at critics of Australia's East Timor policy in an extraordinarily bitter speech that also branded his opposition counterpart Laurie Brereton loopy.

He also warned that military intervention in East Timor, demanded by some to end violence by pro-Indonesian militias, was a ludicrous suggestion that would lead to a catastrophic loss of life.

Mr Downer said critics had overlooked the crucial fact that despite all the grandstanding, the people of East Timor would be deciding their own fate in less than a fortnight.

"The historic significance of that vote cannot be overstated, because less than a year ago such a ballot ... would have been unthinkable," he told the Asia Society in Perth.

"That we have gone from pipe dream to reality in under a year is a remarkable achievement. And it is also due in no small part to the sustained efforts of Australia, a matter which some people in this country wilfully choose to ignore."

Mr Downer used his speech to claim credit not only for persuading Indonesia to change policy and hold the ballot, but for putting together an international coalition to support the decision and the United Nations operation now underway in East Timor.

"Our government is proud of what we have been able to achieve in those few short months," he said. "The success of international action is judged on results – and on East Timor the results are plain to see."

But Mr Downer reserved his strongest criticism for Mr Brereton, whom he labelled one of the "loopiest" of his critics, and other supporters of a military presence in East Timor in the lead-up to the ballot.

Mr Downer has recently been embarrassed by the leaking of documents contradicting his claim that the United States had never raised with Australia a plan to assemble a peacekeeping force for East Timor.

Mr Downer has since been forced to admit the plan was raised but insists it was never official US policy and would have led to catastrophe if ever adopted.

"It is completely ludicrous to suggest that the United Nations, or Australia, or the United States, or any other country could have used military force to impose a settlement in East Timor," he said.

"Not only would that have involved an invasion of Indonesian territory, it would have led to loss of life on a scale that would have dwarfed any of the tragedies we have seen this year on the island."