The investigation comes after police sought court warrants to search 50 houses in two Bangkok projects they suspect were bought by representatives of Chinese businessman Chainat “Tuhao” Kornchayanan.
Chainat surrendered to a police team investigating Chinese criminal gangs on November 23. He denies being the boss of a triad drugs ring.
The housing projects under investigation are in Soi Lasalle and Charoen Nakhon Road.
Department of Lands deputy director-general Panitavadee Prachnakorn confirmed on Thursday that by law, residential projects in Thailand must be owned legitimately by Thais.
"Anyone who owns residential projects in foreigners' stead will face punishment in line with the law," she said.
She said the department will investigate shareholdings and acquisitions of residential projects where proxy ownership is suspected.
Department officials have been instructed to investigate carefully as news of foreigners acquiring land in Thailand has caused unease among the public, she added.
The government recently backtracked on its move to allow foreigners to own residential land after a public outcry.
"Officials have also been asked to publicise that Thais who own land in a foreigner's stead are breaking the Land Code and Criminal Code by making a false statement," Panitavadee said.
Meanwhile, penalties for foreigners found using proxies to own land in Thailand include jail, fines, and having the land seized and sold by the department, she said.
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