About 1,000 indebted farmers rallied on Monday morning in front of the Ministry of Finance, causing heavy traffic congestion around the area, Police Radio FM 91 station reported.
The demonstrators from the Farmers' Reconstruction and Development Fund demanded the government help relieve their burden of debt.
Finance officials were unable to enter the ministry's office building on Rama 6 road because of the protest.
According to FM 91, the farmers' rally caused severe traffic jams on Rama 6 and Phahol Yothin roads, at Pradipat intersection and Saphan Kwai.