The department said in a statement that the 23-year-old was not being detained and arrangements were being made for him to board a flight out of Thailand.
The founder of Thailand’s Miss Grand International pageant, Navit Utsaragrisal, who also represents Han Lee, said she had been in the transit area of Bangkok’s airport since Wednesday afternoon.
Han Lee was stopped on arrival because she was the subject of an Interpol notice, he said.
“She doesn’t want to go anywhere else. She wants to stay in Thailand,” she told Reuters. “She is waiting for a solution on how she can stay in Thailand.”
Myanmar has been rocked by protests since February last year, which was suppressed by the military with deadly force and thousands of arrests.
A spokesman for Myanmar’s ruling military council could not be reached for comment. Interpol did not immediately respond to a request for comment on whether Han Li was the subject of Interpol’s notice.
Han Lee was a contestant at Miss Grand International when videos of her breaking down on stage while speaking about the bloodshed in Myanmar went viral on social media, a day when more than 140 protesters were killed.
In an interview with Reuters last year, he said his people would “never give up”.
Han Lee’s Instagram postings reveal that he has spent most of the past year in Thailand. She was returning home by flight from Vietnam when she was denied entry.
Additional reporting by CNN’s Heather Chen.