The Cabinet approved the move earlier in response to complaints from small businesses about the difficulty of competing with cheap goods from abroad, especially products sold online.
Imported goods selling for less than B1,500 are currently exempt from VAT in Thailand.
The regulation will be in effect until Dec 31, giving authorities time to draft a legal amendment to make it permanent, according to a Ministry of Finance official.
Deputy Finance Minister Julapun Amornvivat earlier this year said that cheap goods from China in particular, which were exempt from customs duties and VAT, were hurting local manufacturers.
Prime Minister Srettha Thavisin also noted a trend of false declarations being made on cheap Chinese products in free trade zones, to avoid VAT, which he said should be imposed.