Several agencies were in the fray, according to a source, and ZenithOptimedia and Dentsu made the the final round, according to another source.
Executives at Havas Media and Havas Worldwide declined to comment. ZenithOptimedia and Dentsu could not be reached by press time. NTUC also declined to comment.
Havas has reportedly held the account since 2008.
NTUC was founded by the labour movement in 1973. It is currently the largest supermarket chain in Singapore with more than 270 stores.