Scott Morrison is campaigning to block a bill that would allow refugees in offshore camps get medical treatment in the country.
"The problem with the bill is it takes control from the government and contracts it out to others who don't have those same interests or responsibilities," Morrison told the Sydney Morning Herald.
Slamming the proposal, that has the backing of the opposition Labour Party, Morrison said it would lead to deaths at sea. "They will unleash a world of woe again."
Under the country’s immigration policy, those who arrive by boat have been sent to camps in Papua New Guinea and Nauru.
The Australian Parliament is expected to vote on the bill on Tuesday.