Seksakol Atthawong has quit his post as an assistant to the Prime Minister's Office minister after a leaked audio recording appeared to suggest he was offering lottery ticket quotas in exchange for a loan for a political campaign.
Mr Seksakol, known as "Rambo Isan", said the clip could damage the "image and credibility" of people working for Prime Minister Prayut Chan-o-cha, and his resignation would take effect on Tuesday.
"I don't want to be a malfunctioning cog which disrupts the progress of the government mechanism," he said.
One of Gen Prayut's closest aides, Mr Seksakol has been under fire following the leak of the conversation with Jureeporn Sinthuprai, another Palang Pracharath politician. He is heard telling Ms Jureeporn he had borrowed 15 million baht from a man to finance an election campaign. That lender turned out to be involved in lottery quotas.
Ms Jureeporn is then heard agreeing to borrow money from another source to repay the 15-million-baht debt. Mr Seksakol then promised to "take care of lottery quotas" for the new lender in exchange for a favour.
The election campaign mentioned in the conversation apparently referred to the general election in Nakhon Ratchasima in 2019. Mr Seksakol lost the contest to a candidate from the Bhumjaithai Party.
Suspected corruption
Mr Seksakol was assigned by the government to crack down on overpriced lottery tickets. His targets were online lottery vendors.
The day the conversation took place was not clear.
The recording of the conversation posted on the Facebook account of lawyer Sittra Biabungkerd on April 1 did not name Mr Seksakol and Mr Jureeporn.
But the two later admitted that they were the man and woman in the conversation. Mr Seksakol claimed he "was joking" with her during the call.
Ms Jureeporn claimed later the clip was secretly recorded by Sudsiam Makkaew, a used-car dealer who was present when she talked with Mr Seksakol over speakerphone.
The two registered a complaint with Dusit police station on April 4 accusing Mr Sudsiam of violating the Computer Crime Act, causing damage to them.
He was ordered to meet the police on Tuesday.
Mr Sudsiam denied that he recorded the conversation.
Mr Seksakol and Ms Jureeporn are members of the ruling Palang Pracharath Party. Ms Jureeporn works as a politician at the Prime Minister's Secretary-General Office.
