Australian Prime Minister Malcolm Turnbull introduced an anti-immigration bill Sunday with stricter regulations to stem the number of asylum seekers who are smuggled into the country by sea. The new bill will also ban these refugees from ever visiting the country in the future.

Turnbull’s conservative government is moving to secure its borders in the wake of the global refugee crisis. The country has already banned asylum for refugees arriving by boat, citing the wave of refugees entering the country using unsafe human smuggling practices.

“The door to Australia is closed to those who seek to come here by boat with a people smuggler — it is closed,” Turnbull told reporters in Sydney. “A generous humanitarian program, a harmonious multicultural society, depends on the Australian government being in control of its borders. And it depends on us sending a united and concerted answer to the people smugglers, that if they seek to bring people to Australia, those passengers will never settle in this country.”

The prime minister added that Australia had already taken in thousands of refugees. The new policy will also affect asylum seekers residing at a regional processing facility in Nauru or Papua New Guinea since July 19, 2013. However, refugees under the age of 18 who enter the country by sea will be exempt from the policy.

Refugees who came to the country by boat since 2012 have been transferred to offshore processing centers in Nauru and Papua New Guinea, making it clear that they would not be allowed to settle in Australia. The country’s leaders have defended the harsh policy in spite of criticisms and reports of abuse in these offshore camps.

Turnbull also urged Leader of Opposition Bill Shorten to back the new bill, calling the proposal “entirely consistent with his party’s public stated position.”

Shorten, however, accused the prime minister of caving in to the view of right-wing extremists in the coalition and said some aspects of the proposed bill were “ridiculous.”

Speaking to Fairfax Media Monday, Shorten said, “It seems ridiculous to me that a genuine refugee who settles in the U.S. or Canada and becomes a U.S. or Canadian citizen is banned from visiting Australia as a tourist, businessman or businesswoman 40 years down the track.”

“Of course people who come by people smuggler should not be allowed to settle here — we will never allow the people smugglers back in business,” he added.

Human rights activists called the new bill “deliberately cruel to innocent people. Daniel Webb, director of legal advocacy at Human Rights Law Center in Melbourne, said the new bill would terrify those already living in Australia and destroy families.

“People who need protection shouldn’t be punished for seeking help,” Webb reportedly said. “We need to open up safe pathways to protection, rather than just closing unsafe ways.”