Australian Greens leader Bob Brown says the imminent defeat of the federal government's migration law changes will be a good outcome, albeit for the wrong reason.
WA Nationals MP Tony Crook, who sits on the crossbench, on Thursday said he would not be voting for the amendments, which would put beyond legal doubt the government's ability to do deals with other countries for offshore processing of asylum seekers.
His announcement means the government won't have the numbers to pass the bill in the lower house.
If that happens, it will be the first defeat of a government bill in the House of Representatives since 1929. Senator Brown, whose party supports onshore processing of asylum seekers, welcomed Mr Crook's decision.
"It's a good outcome, but for the wrong reason," he told reporters in Canberra. "Because the alternative sitting in the wings, there, is offshore processing."
Senator Brown said the move should prompt both the government and opposition to rethink their support for offshore processing.
"(Onshore processing) is increasingly the popular option amongst Australians who want dignity given, not just to asylum seeker but to this nation in the way it handles asylum seekers," he said.
Senator Brown declined to be drawn on whether immigration minister Chris Bowen was doing a good job, but he reiterated his support for the minority Labor government.
"This government is the best option, so I look at the alternatives and think `Thank God this government is in there'," he said.
With the migration bill well down on the list of business for the parliament, it is unlikely to go to a vote on Thursday.
Labor proposed the amendments to back up its asylum seeker swap deal with Malaysia, but the opposition continues to support the previous coalition government's Nauru option.
