A Singaporean man was among 25 people detained at a swingers' sex party in a hotel in Thailand, reports say.

Thai police, along with local officials and soldiers, raided the Ban Tulip Hotel in South Pattaya at about 11.30pm on Saturday night (April 21), rounding up 11 men and 14 women in various states of undress from different countries, the Bangkok Post reported on Sunday.

According to the Post, a swingers' party was being held in a room on the hotel's ground floor, where 25 people were found naked, performing sexual activities.

They included people from America, Canada, China, Malaysia, Singapore, Germany, Thailand, Cambodia, India and Ukraine, who were all detained for further legal action.

Shin Min Daily News said in a report on Monday that a Singaporean man was among those detained.

The hotel operator was arrested for violating the Hotel Act and illegally facilitating sexual activities, the Post said.

Banglamung district police chief Naris Niawpantawong said the police received a complaint about the hotel and were told they organised sex parties on weekends, News.com.au reported.