The Government is reviewing Singapore's laws on corruption, and will increase the Corrupt Practices Investigation Bureau's (CPIB) manpower by more than 20 per cent, as part of efforts to keep corruption at bay.

A one-stop Corruption Reporting Centre will also be set up, to make it easier for members of the public to report cases of corruption.

These measures were revealed by Prime Minister Lee Hsien Loong on Tuesday, as he addressed 600 public servants about maintaining integrity in the public service.

Public servants have been able to do good work for the country, said Mr Lee, because of the trust Singaporeans have placed in the public service.

And to maintain this trust, it is important for the public service to uphold its policy of zero tolerance for corruption, he added.

'If any of you does something wrong, and breaches that trust, you not only let down the public service and yourself, but you are also letting Singaporeans down, and you can do a lot of damage,' he said.

While Singapore was a 'shining exception' in the world, where corruption is a problem in many countries, said Mr Lee, the country must never take this for granted.

Recent high-profile cases of corruption, such as the sex-for-contracts cases involving law enforcement officers as well as the misappropriation of funds by a CPIB branch head, for example, could have affected Singapore's ranking in the Transparency International Corruption Perceptions index, he said.

Singapore fell two spots to be placed seven this year.

'These cases hurt our reputation - they hurt our reputation with Singaporeans, they hurt our reputation internationally,' said Mr Lee adding it was a disservice to the many exemplary officers who had done their part in keeping the public service corruption free.

But he said public servants should not be demoralised when cases do surface.

Singapore should instead be resolved to punish the culprits and remedy the weaknesses in the system.

'This level of trust that the Singapore Public Service enjoys, and this degree of cleanliness in the public service is a most unnatural state of affairs,' Mr Lee said. 'So work doubly hard to maintain the trust you've earned.'