Police confirmed a story in the Himalayan Times newspaper on Tuesday that Paras Shah had spent a night in jail in Phuket on October 23 on a charge of possessing 3.5 grams of marijuana.
The former crown prince was later released on bail of B10,000, it added.
A senior police officer in Phuket told the Bangkok Post the report was true, adding that the former crown prince, the son of ex-King Gyanendra Shah was arrested with a woman at a hotel. He did not identify the woman.
The officer, who spoke on condition of anonymity, said Phuket police had been called by the hotel to break up a quarrel between a man and a woman and they found the drugs while mediating the dispute. The man turned out to be a former crown prince from Nepal, he added.
The woman confessed to the police but the former crown prince decided to fight the charge, the officer said. His passport was taken by police and he has since appeared before the court twice to renew bail.
The Himalayan Times said the Nepalese embassy in Bangkok was informed about the case on October 27. The Nepalese embassy and Thai embassy in Nepal “have remained mum over this matter,” it added.
It also said that Prince Paras Shah had bought an apartment on Phuket “and is living with his Thai girlfriend in Bangkok”.
It is not the first time the prince has been trouble with police. Earlier in 2010, he was arrested by the Nepalese police for attempted murder after allegedly opening fire at the Tiger Tops Resort in the Chitwan National Park after an altercation with the son-in-law of then-Deputy Prime Minister Sujata.