
The video shows a group of people wearing caps and facemasks handing out 100 baht bills along with a candidate brochure to participants at an undisclosed event in the northeastern province.
It was widely shared on social media on Friday.
Wirat Rattanaset, deputy leader of the Palang Pracharath Party, told a press conference on Friday that the party candidate whose brochure appears in the video was framed.
The vote-buying video was a setup, Wirat told reporters.
The party has filed a charge of defamation against the individual who uploaded the video on social media, he added.
“Opponents from other parties probably know they cannot win against PPRP in Constituency 7 so they resorted to using this trick,” Wirat said. “However, this will not harm us, as gold will always be gold.”
Rapipong Jiraphattanaluck, director of the Nakhon Ratchasima provincial office of the election commission, said he had asked headquarters as well as local police to investigate.
The commission said on Friday it has dispatched a rapid-response investigation team to Nakhon Ratchasima.
It expects to quickly determine whether election laws were violated, the commission said.
Nakhon Ratchasima, also known as Korat, is the top battleground province in the Northeast for the May 14 election. It has 2.1 million voters and 16 constituency seats up for grabs.
Pheu Thai, Bhumjaithai, and the PPRP are competing fiercely for constituency seats in the province, which is considered the "Gateway to the Northeast.”