A cabinet-backed draft regulation will allow authorities to remove foreigners whose conduct is deemed incompatible with Thai morals and social norms, Deputy Prime Minister for Legal Affairs Pakorn Nilprapunt said.

He was referring to the draft PM's Office Regulation on Deportation, which was approved in principle by the cabinet on July 14 and is under review by the Office of the Council of State.

He said Thailand already has a deportation law but lacks clear administrative procedures, leaving immigration law to largely replace deportation in practice. Illegal entrants are typically prosecuted, detained and later repatriated.

The existing law, enacted decades ago, requires deportees to be returned by the same route they entered, with transport operators covering the cost.

Mr Pakorn said the provision no longer reflects reality because many undocumented migrants entered long ago without the means to return home, while airlines refuse to bear the expense. 

Foreigners engaging in conduct considered "deviant" or inconsistent with Thai social norms could be deported immediately. Those convicted of serious crimes would first face prosecution but must be deported within 30 days of completing their sentence if a deportation order has been issued.

Mr Pakorn said the government opted to allow state funds to cover deportation costs because repatriation is less expensive than a long detention.

The regulation lists six offence categories that may warrant deportation, including illegal entry or overstay, unlawful employment, illegal business operations and document forgery, among others. It also requires the Corrections Department to notify the Interior Ministry before a foreign inmate is freed so a deportation order can be issued.