A passenger took a photo of a taxi driver extending his middle finger at Central World after he refused to use his meter and ejected the passenger.
The passenger, whose Facebook account is Nitsaphat Meksakul, posted a photo of the driver standing outside the driver's door showing him the middle finger.
Nitsaphat said he has filed a complaint with the Land Transport Department on the 1584 hotline.
The passenger said that the incident on Wednesday evening was witnessed by a female security officer.
Nitsaphat added that he reminded the driver of double penalties for refusing passengers and for not using a meter.
The confrontation happened below a sign warning taxi drivers not to refuse passengers, Nitsaphat posted.
The driver allegedly tried the same approach with a group of foreigners, who walked away.
The passenger was told to pay Bt300 to reach Nonthaburi pier.
Nitsaphat said a group of apparently Chinese tourists agreed to pay a chartered price and the driver took them.