The Pheu Thai Party and representatives of rice growers oppose the government's plan to charge rice growers fees for the use of water from natural sources.
The proposal by the Ministry of Natural Resources and Environment should be shelved because farmers are already indebted and should not face a heavier financial burden, said Chavalit Wichayasut, former deputy secretary-general of Pheu Thai.
He said there was enough rainwater and the government could find ways to manage water resources more efficiently.
Samian Hongto, head of a network of Central Plains rice growers, said farmers' representatives were monitoring the progress of a draft water resources bill, under which farmers and business operators would be charged fees for water usage.
He said the bill would kill rice growers.
The National Legislative Assembly is currently studying the draft bill, which is expected to be passed next month or in November. If it passes, it would mark a milestone given that nearly every government dating back to 1992 has attempted to pass a water resources law with usage fees as well as penalties for water polluters.
If the bill passes, organic laws would be drawn up within 180 days and more public hearings would be held, especially on the rates, Vorasart Apaipong, director-general of the Water Resources Department said recently.
In addition to farmers, a wide range of other water-intensive industries as well as tourism businesses such as hotels could face fees for natural water consumpion.
Mr Samian said that if fees for farmers became mandatory, the government should distribute water directly to paddy fields, and rice growers should have the right to sue the government for flooding.
In any case, he said, the government would have to explain the plan well to prevent undesirable incidents.
Prom Boonmachuay, chairman of a farmers' council in Suphan Buri province, said fees should be charged only to large operators that consume water to excess, including those who had at least 100 rai of paddy fields each.
The bill proposes to exempt rice and sugarcane farmers with less than 50 rai from fees.
Real rice farmers did not consume much water, said Mr Prom. However, he added that he had yet to study the details of the bill.