Three fake Singapore passports were found by Thai police who nabbed a Pakistani national suspected of producing fraudulent travel documents.
But Thai officials denied the fake passports were landing in the hands of Islamist militants.
While better technology is used in passport production and authentication, experts say the problem of fake passports still persists. The incidence of imposters - those who use other people's passports - also appears to be on the rise.
Mohammed Iqbal, 52, was arrested on Sunday at Phasi Charoen district in Bangkok with three fake Singapore passports and one fake Indian passport. He also had plates and laminates used to forge entry visas to France, Italy and Spain.
Police say Iqbal's case was linked to that of a sophisticated Iranian forger called Hamid Reza Jafary, whose network was busted in 2016 after key arrests by the Thai police.
At a press conference yesterday about Iqbal's arrest, Immigration Bureau chief Suthipong Wongpin told reporters: "Don't rush to assume that it relates to only the (Islamic State in Iraq and Syria). From our investigation, this producer would hand his goods to traders… The goods could be sent to any group."
While better technology is used in passport production and authentication, experts say the problem of fake passports still persists. The incidence of imposters also appears to be on the rise.
His comments came three days after Deputy Prime Minister Prawit Wongsuwan was cited by the Bangkok Post as saying that Iqbal "wanted to bring fighters from the Middle East to our country, but we stopped that".
According to Immigration Bureau deputy commissioner Ittipol Ittisarnronnachai, Thai police arrested 10 producers of fake passports in the past two years. He said counterfeit French and Italian passports were coveted by Middle Eastern buyers because it was easier for them to pass themselves off as citizens of these countries.
The fake documents, which are usually made to order, cost upwards of 18,000 baht (S$745) each, according to police.
Investigators told The Straits Times that Iqbal, who had operated in Thailand for many years, married a Thai woman and as a result was able to extend his stay in the kingdom.
Thailand, a major tourism destination as well as regional transit hub, saw more than 35 million visitors last year. Asked about the incidence of travellers detected with fake passports, Police Major-General Ittipol said the numbers have remained stable over the years.
Figures from a fake passport detection system developed by the International Organisation for Migration (IOM), and funded by the Canadian government, give an indication of the scale of the problem.
Its Verifier Travel Document and Bearer equipment and software, designed to check suspicious passports within 10 seconds, have been installed in 15 mostly Asian countries, including China, Malaysia, Myanmar, Thailand and Vietnam.
Immigration authorities in the 15 countries spotted 512 fraudulent passports through the system last year. These made up about one-fifth of the total number of suspected passports that officials ran through the system.
According to figures generated by the system in the 15 countries, cases of fraudulent documents fell from 92 per cent to 58 per cent between 2016 and last year, while the cases of imposters jumped from 8 per cent to 42 per cent.
Mr Donato Colucci, IOM's senior regional immigration and border management specialist, told The Straits Times: "Globally speaking, data show the phenomenon (of fake passports) is not decreasing. Hence this analysis could be valid also in this region."