A group of six Singaporeans were among 35 foreigners rounded up by the Indonesian authorities during random raids on nightspots in Batam over the weekend.
The operation, which started last Saturday and ended in the early hours of Sunday, was led by the local immigration authorities and supported by navy personnel.
The Singaporeans included a 16-year-old student and at least three youths, who were on holiday in Batam.
They were among a total of 27 men and eight women - all foreign nationals - who were detained because they could not produce their passports during the raid at Kampung Bule, an entertainment area in Batam which foreigners are known to frequent.
Most of the revellers were released after they were able to get their travel documents from their hotels for verification. A few remain in custody as investigations continue.
Singapore's Ministry of Foreign Affairs said it "understands that four Singaporean tourists in Batam were initially unable to produce their passports during a check by the local authorities on April 22 as they had left their passports in the hotel".
"They were allowed to return to Singapore with no charges pressed after they produced their passports. The Singapore Consulate in Batam provided the necessary consular assistance to the Singaporeans," said a ministry spokesman.
Video footage of the operation, captured by local news station Gurindam TV, showed an altercation between a naval officer and a group of Caucasian women outside a nightclub.