Australia's highest court Wednesday voided a transfer of asylum seekers to Malaysia, ruling the government's attempt to stem an influx of boat people from poor, war-torn countries could not assure their legal rights would be protected.

The High Court ruled 6-1 to make permanent an injunction that has prevented Australia from transferring 800 asylum seekers to Malaysia in return for Malaysia sending 4,000 registered refugees for resettlement. The ruling cannot be appealed, but the government said it was considering its options.

Government lawyers had argued in court that Australia could lawfully declare Malaysia a safe third country to process refugee claims even though it had no domestic or international legal obligations to protect refugees.

The court said in a statement that Malaysia has not signed the U.N. Convention on Refugees and the deal with Australia did not legally bind Malaysia to recognize the status of refugees under its domestic law. It said any suitable third country must have obligations under international or domestic law to protect asylum seekers and refugees.