Commerce Minister Krirk-krai Jirapaet said civil organisations should rethink their opposition, given that officials had spent the past four to five years working on the "mutually beneficial agreement".

The minister is due to leave for Tokyo today to join Prime Minister Surayud Chulanont, who will head the trade team when the agreement is signed on Tuesday.

Palang Paengdinthai Party leader Likit Teeravekin said the government should not sign the agreement yet. The deal needs approval from an elected Parliament.

Farmers' network representative Ekachai Issara-tha said farmers would be negatively affected by the agreement as far as use of micro-organisms in farming is concerned. The government should suspend the signing and provide the public with more information, he said.

The leader of the North chapter of the People's Alliance for Democracy, Siriyan Thongnoo-ead, said the agreement would turn some government supporters into opponents as a result of the deal's negative impact on poor people.

"This government should focus on solving poverty. Most people feel Prime Minister Surayud has not done anything significant for the rural poor," he said.