THOUSANDS of Cambodians working as migrant labourers in Thailand may face abrupt deportation in the coming weeks, the UN’s special rapporteur on the human rights of migrants said Thursday.

February 28 is the deadline set by Thailand for migrant workers to register for nationality verification through their home governments, extending their work permits. Those who fail to register will be subject to deportation, a policy UN rapporteur Jorge Bustamente sharply criticised.

“If pursued, the threats of mass expulsion will result in unprecedented human suffering and will definitely breach fundamental human rights obligations,” Bustamente said in a statement Thursday.

Though international concern has focused primarily on Myanmar migrants, Cambodians may also constitute a significant percentage of the deportees, said Andy Hall, director of Thailand’s Migrant Justice Programme.

As of February 8, some 70,047 Cambodian migrants had completed the nationality verification process, according to Thailand’s Ministry of Labour. Many thousands more – both documented and undocumented – had yet to register, Hall said.

Ministry of Foreign Affairs spokesman Koy Kuong said the Cambodian government had sent a working group to Thailand to assist in the process.

“This is normal for the internal affairs of Thailand because they’re implementing immigration law,” he said.

Chawanon Intharakomansut, secretary to the Thai foreign minister, said nationality verification was a well-publicised aspect of Thailand’s labour law, and that it had been going “very well”. “We’ve got cooperation from all the countries” involved, Chawanon said.

Hall said awareness of the policy was limited, and that even migrants who knew of the process were constrained by the brokers’ fees required to secure verification. Thailand, he said, should recognise the benefits of having migrants and adopt a more conciliatory approach.

“The economy is incredibly dependent on these people,” he said. “If they did go ahead with [deportations], it would be very concerning.”