Police arrested more than 120 people wearing only underwear in a Bangkok hotel room where they were partying with drugs early Sunday morning.

Police stopped the party in Room 2001 on the 20th floor at S31 Hotel in Watthana district at 1.30am on Sunday.

In the room, police found 124 Thai and foreign men, described as gay, in their underwear, along with a few women and some ecstasy and ketamine.

Police were told of a similar party in the same hotel room from Friday night to Saturday morning.

They learned that participants had to apply for admission via a private social media group. Plainclothes police had also done so but the group rejected their applications.

Early Sunday morning, police were informed that many people were again entering Room 2001 and it was likely that another party with drugs was being organised.

After entering the room that morning, police found the men were eating, drinking and listening to music in the large room. Police seized drugs and brought all participants for tests.

Test results later determined that 31 people, including one woman, had been in possession of drugs and 66 others, including another woman, had consumed them.

A source said that the partygoers included doctors and beauty clinic operators.