Free trade talks with Japan and the US have been postponed indefinitely, until Thailand forms a new government.

The country's prime minister, Thaksin Shinawatra, has called a snap election for 2 April, and trade negotiations cannot proceed without a political mandate, reported The Wall Street Journal Asia.

Thailand was due to sign a free trade agreement on 3 April that would go into effect in October. This may now be delayed until next year.

A free trade agreement would open up the Japanese market to vehicle exports from companies such as Toyota, GM and Ford, which have made Thailand a manufacturing hub for pick-up trucks.

A free trade agreement with the US, the world's largest market for pick-ups, is also under negotiation. The US currently levies a 25% tarirff on imported pick-ups from Thailand.