The telco has issued a Request for Information to all agencies with a deadline of 25 September, and has invited incumbent Y&R to contest the review.
Sherie Ng, SingTel's director of brand experience, said in a statement: "The decision to embark on a creative agency search process was made to secure the best services available in the global marketplace for SingTel's future business needs."
She added: "This is in keeping with the extensive changes in SingTel's business environment, expanding business portfolio and global presence as well as the dynamic changes in the media landscape."
The pitch is part of the company's periodic review of its suppliers. It will be managed by R3, and is expected to be concluded within 16 weeks.