The measure, aimed at checking the spread of the Covid-19 virus, will remain in effect until September 30.
Anupong said visitors must apply for visas in their home countries and bring a certificate of sound health.
Visitors from hard-hit locales Italy, South Korea and Hong Kong also become ineligible for visa-free entry, he said.
The 18 countries are Bulgaria, Bhutan, Cyprus, Ethiopia, Fiji, Georgia, India, Kazakhstan, Malta, Mexico, Nauru, Papua New Guinea, Romania, Russia, Saudi Arabia, Uzbekistan, Vanuatu and “China (including Taiwan)”.
A government panel made the call on Wednesday at a meeting chaired by Prime Minister Prayut Chan-o-cha, who is also heading the Covid-19 management centre.
Prayut and Anupong signed off on this Interior Ministry order on Thursday.
However, Department of Consular Affairs' director-general Chatree Atchananant said earlier today that there would be no official announcement of the measure until the Cabinet considers it on March 17, before Anupong came out later to confirm that the measure would be implemented tomorrow (March 13).