The Public Service Division will review if tighter rules with regard to civil servants visiting casinos should be put in place, especially for officers who work in areas where there may be potential conflict of interest, said civil service head Peter Ong.

The comments, seen in his email sent to all public officers on Friday afternoon, comes after an assistant director from the Corrupt Practices Investigation Bureau (CPIB) was charged in court this week with siphoning funds from the anti-graft agency's account to feed his gambling habit at the Marina Bay Sands casino.

Mr Ong, referring to the findings of a study conducted by the Home Affairs Ministry earlier this year to establish if there are systemic issues within the public service, said that while the "system as a whole remains sound", public officers cannot be complacent.

The same study had found that the number of cases opened for investigation on public officers for corruption and other financial crimes remained low and fairly stable between 2008 and 2012, but Mr Ong added: "Every case is one too many."

Such cases, he added, "cast a pall" over the honest work done by the majority of civil servants daily, and urged civil servants to guard the trust that fellow citizens have in them and in the public service.

"Trust takes years to build, seconds to break, and a long time to repair. As guardians of this trust, we must always be watchful," he said.