Sansern Samalapa, Atthawit Suwanpakdi and Chanin Rungsaeng took turns criticising the government's handling of the economy in the face of a rise in liquefied petroleum gas (LPG) prices, electricity tariffs and expressway tolls which took effect Sunday.
Mr Sansern said consumer spending was slowing due to hefty household debts. The situation has not reached rock bottom but it could worsen in a month or two if state spending was not accelerated to stimulate the economy.
He said the only measure that was deemed appropriate was to speed up the government's budget disbursements.
"But the problem is that the budget can't be disbursed. If the government had followed the Democrat Party's advice that the 350-billion baht borrowing plan [for water management] be included in the regular spending plan, the money would have been flowing into the system," he said.
He also slammed the government for making excuses when signs of economic problems appeared.
He was referring to Prime Minister Yingluck Shinawatra's claim last year that the idea that prices were on the rise was just a "public perception".
Recently, Deputy Prime Minister Kittiratt Na-Ranong claimed second quarter contractions stemmed in part from the long public holiday over Songkran.
Mr Atthawit said both household debts and public debts have soared since Ms Yingluck took office two years ago.
Mr Atthawit said household debts account for 78% of GDP, and is threatening consumer spending.
He said the government still had a chance to make amends by reviewing any policy that would raise the cost of living.
"If household debts rise to 80%, consumer spending is likely to stop. What is left to do is to increase the state spending," he said.
"But we face a difficult situation because the government doesn't know how to handle it."
Meanwhile, civic networks Sunday launched a campaign to seek the removal of Energy Minister Pongsak Raktapongpaisal and four senior officials over the cooking gas price hike.
They set up a booth outside the head office of PTT Plc on Vibhavadi Rangsit Road and collected signatures to support the impeachment bid. The petition requires 50,000 voter signatures.
The groups accused the minister and the officials of negligence of duty and abuse of authority in the government's cooking price increase.
A mass rally will be organised outside the head office of PTT Plc next Monday after the signature collection campaign wraps up on Sept 8. The groups last week petitioned the Administrative Court asking it to issue an injunction to suspend the cooking gas price hike.
Meanwhile, the rise in the cooking gas price for households and expressway tolls would not cause inflation to rise significantly, Thanawat Polvichai, director of the Economic and Business Forecasting Centre at the University of the Thai Chamber of Commerce said.
Mr Thanawat said the increase in LPG price for cooking by 0.50 baht per kilogramme per month, or by 3%, would have little affect on Thailand's inflation.