A last-minute rush of largely Cambodian, Burmese and Laotian undocumented workers is expected to descend today on Thailand’s one-stop service centres for visas and work permits (OCCS), as Thai authorities yesterday signalled a crackdown on illegal labour.

More than 100,000 Cambodian workers in Thailand could face arrest and deportation after the deadline for reapplying for a work permit extension came and went yesterday.

“There are a significant number of workers at risk of arrest and deportation, or as usual, arrest, extortion and release … [among] the most prominent features of Thai migration policy for decades now,” said Thailand-based migrant expert and workers’ rights advocate Andy Hall.

The Thai government had previously pushed back a March 31 deadline, giving undocumented workers until yesterday to extend their work permits for a year, in which time they were expected to be issued passports by their respective governments.

Hall added it was simply “not possible” to re-register the huge number of workers in time, raising the possibility of a repeat of last year’s mass exodus, when some 225,000 Cambodian workers fled back across the border after the Thai junta cracked down on illegal migrants.

According to figures from Thailand’s Office of Foreign Workers Administration, 738,947 Cambodian migrants, 696,338 workers and 42,609 dependents registered at OCCSs last year.

Of these, 173,467 had the correct documents. As of June 22, a further 391,628 had reapplied for a work permit.

This leaves more than 130,000 at risk of deportation.

Quoted by Thai state media yesterday, Thailand’s Deputy Permanent Secretary of the Ministry of Labour Sumet Mahosot warned that the Department of Employment would start monitoring workplaces and penalising employers and employees who missed the deadline.

Mahosot said 990,716 migrants had renewed their permits as of Monday, and he expected that number to surpass one million today.

He did not, however, break down the numbers according to nationality, or indicate how many previously registered migrants were yet to reapply.

Omsin Boonlert, a Chiang Mai-based research officer for the Mekong Migration Network, said many illegal migrants were hoping that the authorities will offer a reprieve and extend the deadline again.

Boonlert said the work permit process, largely dependent on employers, was made difficult as many companies lacked “cancellation” documents from their employees former workplaces.

Prices for the renewals were also much higher than the stated rates, with brokers and officials known to add extra fees, she said.

Spokesmen for Cambodia’s Foreign and Labour Ministries could not be reached.

Banteay Meanchey Governor Korsum Saroeut reported no additional activity at the border as of yesterday.

“Now we are waiting for a decision,” said Saroeut, who sits on a recently established committee created to help Cambodian workers if deportations begin. “In 2014, we did not know anything and then Thailand sent the workers back.”