The Australian government has suffered an historic defeat, losing a vote on the floor of the House of Representatives for the first time since 1941.
The Opposition Australian Labor Party (ALP) joined forces with the Greens and independent Members of Parliament (MPs) to pass the medical evacuations bill by 75 votes to the governing Liberal-National Party coalition (LNP)'s 74.
The bill, which now goes to the Senate where the LNP holds only 31 out of 76 seats, will force the medical transfers of asylum seekers being held in offshore detention to Australia if two doctors agree it is necessary.
Under the previous system, the Minister for Home Affairs, currently Peter Dutton, had final say over all proposed medical transfers.
Addressing the defeat on Tuesday night, Prime Minister Scott Morrison, who oversaw the implementation of Australia's hardline border policies during his time as immigration minister, accused ALP leader Bill Shorten of prioritizing political games over national security.
"Every arrival is on Bill Shorten and Labor's head. Every arrival," he told reporters in Canberra.
The vote has paved the way for border protection to be a major issue in the general election, which Morrison on Tuesday said would be held in May despite the historic defeat.
Immediately after the vote Morrison and Dutton met with the Australian Border Force (ABF) to implement "contingency measures."
"The priority for me having met with the general of Operation Sovereign Borders is to deal with the difficult circumstance that Bill Shorten created," Dutton told Australian Broadcasting Corporation (ABC) television.
"I think most Australians now see fortunately before the election, unlike the case with (former ALP PM Kevin) Rudd, a Labor Party unravelling a successful border protection policy. "That's a disaster for our country."
Earlier on Tuesday, the ALP made some compromises on the bill, introducing amendments to give the Home Affairs Minister the power to overrule a medical transfer on specific security concerns and making changes to avoid a possible breach of the Australian Constitution.
"The government tells us that this bill is a constitutional crisis. The fact of the matter is this bill is about providing treatment to sick people," Shorten told Parliament."We can have strong borders while still fulfilling our duty of care to the people in our care."
Kerryn Phelps, the independent MP who championed the bill and who previously served as President of the Australian Medical Association (AMA), described the vote as "such an important day for sick people needing medical care they are unable to receive."
"Thank you to all of the many people who contributed to this remarkable community campaign," she wrote on social media.