The Malaysian authorities' arrest of a Bangladeshi migrant worker who was featured in an Al Jazeera documentary was clear retaliation for his criticism of government policies towards migrants, Human Rights Watch said today.

The authorities should immediately release Rayhan Kabir, 25, and reinstate his work permit, said the global rights group in a media release.

"The Malaysian authorities' actions against Kabir send a chilling message to all migrant workers that speaking out about rights abuses risks arbitrary arrest, deportation, and blacklisting," said Phil Robertson, deputy Asia director of HRW.

"The arrest of a source in a documentary adds to the devastating assault on free speech and media freedom in Malaysia," he said.

Rayhan was featured in an Al Jazeera documentary that aired on July 3 about the treatment of migrant workers in Malaysia during the Covid-19 pandemic lockdown.

The government targeted both Rayhan and Al Jazeera, with the news agency now facing potential charges of sedition, defamation, and violation of the Communications and Multimedia Act.

Al Jazeera is also facing charges that it failed to obtain a licence to make the film in an unprecedented use of Malaysia's National Film Development Corporation Act.

The authorities arrested Rayhan on July 24, 2020 and ordered his detention for 14 days "for investigation."

The director general of immigration announced that Rayhan "will be deported and blacklisted from entering Malaysia forever." It is not clear whether he will also face criminal charges.

On the day of his arrest, Rayhan wrote to a journalist saying, "I did not commit any crime. I did not lie. I have only talked about discrimination against the migrants. I want the dignity of migrants and my country ensured. I believe all migrants and Bangladesh will stand with me."

A group of 21 Bangladeshi civil society organisations called for Rayhan's release.

Rayhan's treatment by the authorities has raised important due process concerns, HRW said.

After the documentary aired, the authorities widely circulated a "search notice" that included his photo, name, and address, putting him at risk in an environment increasingly hostile to migrants.

A few days later, the inspector general of police in Malaysia announced to the media that the immigration department had revoked Rayhan's work permit. This, along with the announcement that he would be deported and blacklisted, was made without Rayhan receiving notice or having an opportunity to be heard.

The government's public attacks on Rayhan, at a time of rising xenophobia in Malaysia, serve to fan the flames of intolerance, HRW said.

International human rights protections normally apply to non-nationals as well as citizens, including the rights to freedom of expression and due process.

The arrest of Rayhan and investigation of Al Jazeera are part of a larger crackdown on freedom of expression and media freedom in the country, with numerous journalists, civil society activists, and ordinary citizens facing investigation and prosecution for speech critical of the government.

"Speaking to the media about the treatment of migrant workers is not a crime, nor is reporting on such abuses," Robertson said.

"The Malaysian government should release Kabir and engage with the criticism to improve respect for human rights in the country."