The government's rejection of calls to extend the deadline for its nationality verification scheme could lead to more trafficking and extortion of migrant workers, a labour advocate said.

Adisorn Kerdmongkol, a coordinator for the Migrant Working Group, yesterday urged the government to reconsider its decision not to extend the deadline as many migrant workers in Bangkok, Samut Sakhon, Samut Prakan and Tak's Mae Sot district had yet to complete the procedure.

Most of the migrant workers did not have the documents necessary to register, Mr Adisorn said. He added that in many cases the details in the documents obtained by employers and their migrant labourers were different.

However, Labour Minister Padermchai Sasomsap has rebuffed calls to extend the deadline, which passed on Friday.

Action would be taken against migrant workers who are deemed to be staying in Thailand illegally, he said.

But Mr Adisorn warned that the measure to force the workers back to their countries of origin after the deadline could lead to an increase in human trafficking and extortion.

According to group, there are about 2-2.5 million migrant workers in Thailand. About 1.05 million of them had undergone the verification process as of October.

This means over one million migrant workers remain unverified.

These workers, Mr Adisorn said, would be employed illegally and that means Thailand would confront the same problems it has had in the past regarding illegal migrant workers.

"The authorities must extend the nationality verification process for some time," Mr Adisorn said. He added that the process should also be open to migrant workers who lack documents.

Meanwhile, International Labour Organisation director-general Guy Ryder yesterday inspected seafood processing factories in Samut Sakhon's Muang district.

He was there to discuss child labour and human trafficking with Thai authorities.

Mr Ryder supported Samut Sakhon Governor Chulapat Saengchan's commitment to improve children's educational opportunities as a means of tackling the child labour problem.

He said child labour and human trafficking in the seafood industry have been under the scrutiny of the international community and he expected Thailand to be able to tackle the problem in a sustainable manner.

Mr Padermchai said yesterday he hoped the ILO chief would relay Thailand's intention to address these problems to the US so that Thailand would be withdrawn from the US's Priority Watch List for Human Trafficking.