The group of tourists managed to haggle the officer down from his original demand of 60,000 baht, it was alleged.
The allegation was made on a call-in TV talk show and posted on a Line group for tour guides in Chonburi province.
The incident allegedly began soon after the traffic officer spotted a group of Chinese tourists strolling through Pattaya with vaping devices late on Saturday night and ended in the early hours of Sunday.
Vaping devices are illegal in Thailand. So is extortion.
The public relations unit of Chonburi police said on Wednesday that a preliminary probe by Pattaya police found there were sufficient grounds for a full investigation of the allegation.
Chonburi Police commander Maj-General Kampol Leelapraphaporn transferred the traffic officer who allegedly took the bribe – Senior Sgt-Major Noppakrit Pornwatanathankit – to an inactive post at the provincial headquarters on Tuesday, the police PR unit said.
Kampol also ordered that a committee be set up to fully investigate the allegations that Noppakrit took a bribe, it said.
The incident follows the high-profile scandal that erupted after seven officers from Huay Kwang police station were accused of extorting 27,000 baht from a Taiwanese actress in exchange for not charging her for carrying a vaping device. Actress Charlene An subsequently used social and TV media to tell her story of being shaken down by Thai police on January 5.
Kampol has ordered investigators to gather evidence from security cameras as well as witnesses. Legal action will be taken against the officer if he is found guilty, he said.
Kampol also urged residents of Chonburi province to alert his office if they see any misconduct by police.