From Tuesday, all public servants will have to declare their visits to local casinos if they go more than four times a month, or if they purchase an annual pass.

The declaration must be made within seven days, said the Public Service Division (PSD) on Monday.

For officers "whose misconduct will have significant reputational risk to the Public Service," every visit to a casino must be declared to their superiors, it added, but did not specify who would be subject to this more stringent rule.

The new regulations come in the wake of several high-profile cases of misconduct by top public servants.

Besides the corruption trials of former Singapore Civil Defence Force chief Peter Lim and former Central Narcotics Bureau head Ng Boon Gay, an assistant director with the the Corrupt Practices Investigation Bureau, Edwin Yeo, was charged last month with misappropriating $1.7 million from 2008 to last year.

This was apparently to fund his gambling habit at the Marina Bay Sands casino.

From January, the PSD will also enforce mandatory job rotation and block leave for public servants in vulnerable positions. For example, positions where the incumbent may be subject to temptation or exploitation will be filled with someone new every five years.

Officers whose work is "transactional in nature" will be subject to mandatory block leave of at least five consecutive working days per calendar year.

The Public Service also highlighted five principles in its code of conduct, which has been updated after a review started in September last year. They are:

- Work with the elected Government to serve the people of Singapore, and shape Singapore's future

- Uphold the integrity and reputation of the Public Service

- Ensure there is no conflict of interest between our official duties and

personal interests

- Be fair and impartial in carrying out our responsibilities, and not be

corrupt or seen to be so

- Exercise prudence in managing public resources