More than 100 officers from Jurong police division, the Criminal Investigation Department and Gurkha contingent were involved in the operation near Woodlands Avenues 4 and 9 which flushed out 38 men and 16 women of various Asian nationalities. Their ages range from 25 to 50.

They were found in about 20 makeshift wooden huts in the forested area as officers caught them by surprise in a well-coordinated raid, said police on Tuesday night.

The women will be charged in court on Wednesday while the men will be released on bail pending further investigation.

"Police take a serious view of persons engaging in such illegal vice activities and will not hesitate to take action against all parties involved," warned a police statement.