A day before South Korean rap sensation PSY brings his Gangnam Style to Thailand, scores of inmates have danced to the hit behind barbed wire and bars in a Bangkok prison.

Seventy out of 4,500 prisoners at Bangkok Remand Prison put on a show on Tuesday for the media and corrections department executives after competing in a Gangnam Style dance contest last week.

Officials said the program was to relieve inmates' stress and help them keep fit.

PSY's Gangnam Style in November became the most watched video ever on YouTube. It has spawned hundreds of parodies and tribute videos, including a popular one earlier in 2012 by members of the Thai navy.

PSY will perform in Thailand on Wednesday night - his first show in Asia outside of South Korea.