The Manila Economic and Cultural Office (MECO) on Tuesday urged Filipinos working in Taiwan to be careful, after authorities busted syndicates and individuals engaged in identity theft and electronic fraud.

MECO said some Filipinos have become victims of unauthorized use of their automated teller machine (ATM) and mobile phone subscriber identity module (SIM) card, prompting authorities to issue the advisory.

MECO said at least four Filipinos were held by Taiwan immigration after their names appeared in law enforcement records as having been involved in bank fraud cases.

"It turned or that they were victims of a syndicate who used unclaimed ATM cards from a loan shark to carry out illegal transactions," MECO said.

Last year, Taiwan police arrested a Taiwanese-Filipino couple engaged in illegally lending money to Filipino factory workers in exchange for their ATM cards from where they extract payments for the loans.

Most of the workers no longer got their ATM cards back which were illegally sold by a nephew of the suspects to online fraud syndicates for NT$5,000 each.

MECO Chairman and Resident Representative Angelito Banayo said the modus began in 2012, and believes there could be more Filipinos who are unaware that they were victimized by syndicates.

He said another report uses free SIM cards to entice potential victims. Their identities will be used by the syndicates' illegal activities such as prostitution or drug trafficking.

Banayo has advised Filipinos in Taiwan to immediately contact the local police and the MECO offices in Taipei, Taichung, and Kaohsiung for assistance.