Two holders of fake passports on missing Malaysia Flight MH370 are the latest example of a booming business in fake documents in Southeast Asia.

The two used the passports of a 30-year-old Austrian and a 37-year-old Italian to board the flight from Kuala Lumpur to Beijing.

Gangs in Thailand use stolen passports and fake identities to forge new passports that allow passengers to evade patchy security checks and fly to their destinations, a Reuters report said on Monday.

Malaysian officials released a photo of one of the fake-passport holders on Tuesday afternoon. The man, identified as 19-year-old Iranian Pouria Nour Mohammad Mehrdad, was not believed to be a terrorist. The other person's identity is still being investigated.

According to their tickets, after Beijing, both were booked on other flights, one to Frankfurt and the other to Copenhagen.

Malaysian Home Minister Datuk Seri Ahmad Zahid Hamidi said on Tuesday that the department was linked to Interpol but details of the two passports were not in the list.

"That was why the use of the stolen passports were not detected," he said, adding authorities were working with Interpol to identify the second man who had traveled using the lost papers of Italian Luigi Maraldi.

Britain's Daily Telegraph reported on Tuesday that the two men had both been identified as Iranian nationals. A BBC report quoted an Iranian friend of one of them as saying the fake-passport holder was planning to immigrate to Europe.

Travel agency owner Benjaporn Krutnait from Thailand, who sold the tickets, said a long-term business contact she knew only as "Mr Ali" had booked the two tickets on March 1, asking for the cheapest route to Europe. But there was no evidence that Ali knew they were traveling on fake passports, The Financial Times said.

"There could have been a business chain facilitating illegal entries to Europe — stealing passports in Thailand where there are a lot of international tourists and taking off in Malaysia where the security check was loose," said Xu Liping, a researcher at the Chinese Academy of Social Sciences, told Beijing-based newspaper The Mirror.

"Security checks at Malaysia's airports and subways are rather feeble," said Hong Daode, a criminal procedure law professor at China University of Political Science and Law.

Malaysian security authorities have not conducted any checks through the Interpol passport database. In fact, the two passports had been stolen in 2012 and 2013 in Thailand and already been registered in the Interpol database, Hong said.

Malaysian authorities have denied there were major security loopholes at Kuala Lumpur airport.

The stolen passports on flight MH370 have drawn attention to a booming black market in counterfeit documents in Southeast Asia — where a criminal network of passport thieves and forgers serves shadowy travelers.

Reuters quoted the Thai Ministry of Foreign Affairs as saying that more than 60,000 passports were reported missing or stolen in the country from January 2012 to June 2013.

Interpol said on Sunday that passengers were able to board aircraft more than 1 billion times in 2013 without their passport data being screened through its extensive database, and only some countries use the database frequently and effectively.

That database contains more than 40 million entries with passport information and receives about 800 million searches annually. About half of the searches are from the United States, the United Kingdom and the United Arab Emirates.

Dai Peng, director of the Criminal Investigation Department at People's Public Security University of China, said the two passengers with the fake passports were likely attempting illegal immigration rather than terrorist activities because their major concern was the ticket price instead of the route of travel.

"But it is still a mystery how the two Iranians arrived in Malaysia. And the incident has indeed exposed the loopholes in the Malaysian security department," Dai said.

Many Southeast Asian countries have ramped up their security checks since the Malaysian aircraft disappeared.

Contact the writers at chengyingqi@chinadaily.com.cn and zhangyan1@chinadaily.com.cn

The Star in Malaysia and Asia News Network contributed to this story.