Bangkok - To halt the flow of illicit Chinese garlic over Thailand's northern border the Commerce Ministry has asked that border patrols be stepped up, said local news reports Wednesday.

The commerce ministry has asked Prime Minister Samak Sundaravej to protect the local garlic market where the pungent bulbs sell for twice the price of the smuggled Chinese variety, reported the Nation newspaper.

At least 300,000 tons of illegal garlic has been found in Thailand, when the official quota for Chinese garlic is a mere 10,000 tons, said officials.

The director-general of the international trade department, Yangyong Phuangrach, is quoted as having requested special military squads to man border checkpoints.

A bilateral trade agreement between China and Thailand went into force in 2003 and since then "waves" of smuggled garlic have come over the border, the ministry said.

Big retail operators like Carrefour, Tesco Lotus and Makro have confirmed they only purchase locally grown garlic, said Yangyong.

Thailand produces 80,000 tons a year of garlic which is a vital ingredient in many classic Thai dishes. (dpa)