New Thai laws could see undocumented Cambodian workers sent to prison for up to five years or given fines of almost $3,000, according to an announcement issued by Thailand’s Ministry of Employment.

An English-language summary of a new royal ordinance signed on June 17 says that “foreign workers who engage in work without having the work permit . . . shall be liable to imprisonment for a term not exceeding 5 years or a fine of [$5,860 – $2,945], or both”.

Employers of undocumented foreign workers could face fines from $11,778 to $23,571 per worker, it says, while brokers would face from three to 10 years in prison and fines of $17,678 to $29,455 per worker they provide.

“This legislation will open enormous opportunities for extortion,” Chonticha Tang, programme coordinator at Human Rights and Development Foundation in Thailand, said in an email, explaining that she believed it opened a path to bribe workers with threats of arrest and fines.

She said the law not only targeted undocumented workers but also those “who work somewhere outside their registered location, or work for employers whose name is not the same as that identified on the worker’s card”.

Chonticha also noted that under the law only undocumented workers, and not employers, could face prison.

With the so-called “pink cards” programme – a scheme to provide temporary documents to previously undocumented migrant workers – to end in March, Tang added, many foreign workers will soon be undocumented.

Laurie Parsons, a researcher who works on migration issues, said he believed the new law was “more politics than economics” and questioned whether Thai authorities would ever seek to carry out mass arrests.

“Eliminating hundreds of thousands of irregular migrant workers at a stroke would be economically extremely damaging to Thailand, whose construction, agricultural, fisheries and textiles sectors amongst others are reliant on migrant workers,” Parsons said.

However, Kamontit Bueatsong, an official at Thailand’s Ministry of Employment, said the government had passed the law “because we have irregular migration workers . . . so we want to force the law to be strong”.

Kamontit said the law came into effect on Friday. She directed further questions to the Department of Alien Workers, who could not be reached this week.

Mom Sokchar, programme manager at the local NGO Legal Support for Children and Women, said he believed the new law would inevitably hurt Cambodian migrants workers.

“The problem is the migrant workers never understand the law,” Sokchar said. “Some people have a passport and think they can work legally.”

“Their intention is never that they want to work illegally in Thailand, but they’re forced to . . . because of other reasons such as poverty or lack of labour.”

Chonticha, of the Human Rights and Development Foundation, said the situation may only get worse next year when the pink cards expire and hundreds of thousands of workers potentially again go undocumented.

“They said they’re not going to open for any more rounds of pink card renewal,” she said. “So we don’t know whether the government has any plan at all.”