He informed caretaker Commerce Minister Somkid Jatusripitak in writing about his decision.

"He submitted the letter via caretaker Deputy Commerce Minister Preecha Laohapongchana yesterday morning, giving the reason that he wants to focus on his main task as a TTR," the source said.

Parnpree was not comfortable working under political pressure, the source said.

The Public Warehouse Organisation (PWO) is known as a state-run agency manipulated by politicians for personal gain.

Political interference has hampered Parnpree from achieving his goal of seeing the PWO turned into a practitioner of good governance, the source said.

Parnpree was appointed by the Cabinet last October to solve the organisation's corruption problems - including the dilution of rice quality and murky hiring of rice surveyors - and to seek penalties for the offenders.

Another task was to re-engineer PWO's outdated operations so it can stand on the front line as the ministry's marketing arm. Parnpree said he wanted to quit because he needs to pursue his responsibilities in the TTR office.

"Trade and international trade are key drivers of economic growth. My duty is to help boost exports by encouraging both local enterprises and exporters to take maximum advantage of any bilateral and multilateral trade agreement which Thailand has inked with trading partners," he said.

His main mission - cleaning up the rice pledging scheme, such as by opening up the bidding process for rice-survey concessions - has been accomplished, leaving only the organisation's re-structuring plan, he said. That job will be passed on to the new board head. "I'd like to focus more on my TTR position to strengthen the country's competitiveness in the global arena," he said.

Somkid said the PWO urgently needed overhauling because it has been an "ATM" for corrupt officials and politicians for decades.

Achara Pongvutitham,

Petchanet Pratruangkrai

The Nation