"These unlawful deportations are ripping families apart and causing untold suffering," HRW 's deputy Middle East director, Joe Stork, said on Sunday.
"Bahrain should stop the deportations immediately and restore citizenship to those who have been left stateless, especially when this was done without justification or because they criticized their government," he added.
The New York-based rights group says the tiny Persian Gulf kingdom has deported at least five people after revoking their citizenship and leaving them stateless since February 21.
The HRW said another nine activists risk the same fate if an appeals court in Bahrain on Tuesday does not overturn the decision to strip them of their citizenship.
It stressed that the court decision against activists has been based on a vague accusation that they had “damaged state security.”
Meanwhile, Taimoor Karimi, one of the nine who risk deportation, told HRW that he was deeply concerned about being forced to another country away from his family and with no papers. "I am not a young man," Karimi said, adding, "This does not make sense."
The international rights group has also expressed serious concern over a December 2015 court ruling that gives the Al Khalifa regime a free hand to strip activists and protests of their citizenship.
HRW said the ruling authorizes the Manama regime not provide "specific means of proof" when revoking the nationality of citizens who "cause harm to the state" or fail in their "duty of loyalty."
Reports indicate that over 250 Bahrainis have been stripped of their citizenship since the start of an uprising in the country in 2011.
Also in late January, the HRW criticized Bahrain for failing to stop torturing political prisoners and dismissed Manama’s much-hyped claims of reforms.
“Bahraini authorities have failed to stop torture and failed to address the culture of impunity that fosters torture,” the Middle East director at Human Rights Watch, Sarah Leah Whitson said on January 28, adding, “The much-ballyhooed reforms will remain false advertising until Bahrain stops jailing activists and opposition leaders, holds officers accountable for serious abuses like torture, and gets serious about judicial and security service reform.”
Since mid-February 2011, multitudes of protesters in Bahrain have held numerous peaceful rallies in the streets of the island kingdom, demanding their inalienable human rights. The demonstrators gradually demanded that the Al Khalifa family relinquish power.
In response, the regime has dealt with peaceful protesters with a heavy-handed crackdown, killing scores of people and injuring and arresting many more.