Social media influencer Sean Buranahiran is under fire for posting a video praising Deputy Prime Minister Prawit Wongsuwon as "kind of sweet", upsetting many of his followers.

"I just met General Prawit Wongsuwon. He's not like the one we saw in the meme picture, the one where he sleeps and the one that looks kind of evil," he said in the video posted on Tuesday.

"When I saw him in real life, he's kind of sweet," Mr Sean said.

He did not say when he met the deputy prime minister.

Gen Prawit attended a tree-planting event in Chiang Mai on May 21. It is believed the two men met there.

Mr Sean's video had drawn 17,000 comments as of Thursday morning, many criticising him for his support for the deputy prime minister. One asked whether he really knew Gen Prawit well enough to make such a judgement. 

As the displeasure spread, an online campaign was launched to "unfollow" him on social media, and his fans on Facebook dropped by a million, only to bounce back later.

Mr Sean, 28, has Thai parents but was born and raised in the United States. He later moved to Thailand, introducing himself on Facebook in 2016 

He calls himself a YouTuber, influencer and interviewer. His Facebook page has almost 4 million followers and about 1.5 million follow his YouTube channel.

Gen Prawit said on Thursday he could not remember whether he talked to Sean in Chiang Mai last month, or not.