"Take ownership of causes or issues that you feel strongly about – whether they reflect the aspirations of your constituents or address broader national concerns.
"Champion the issues, and do so with conviction. Effective advocacy goes beyond speaking up. You have to research the issues thoroughly, engage diverse stakeholders, understand the trade-offs, and present well-reasoned arguments for improving policies."
PAP should also be ready for sharper questioning and debate in Parliament, he added, and MPs should be prepared to engage the Opposition, clarify their interventions and scrutinise their ideas.
But he cautioned to exercise good judgement.
"Put your points across with clarity and purpose, address the issues and not the person, and do not get carried away playing to the gallery."
Noting that social media is a key communication and a primary source of news for many, PM Wong urged MPs to "make full use" of the different platforms to inform the public about their work, share their views, and engage residents directly.
"Be honest, empathetic, and constructive in all your messages. Know your audience and be sensitive to how they feel. Do not use social media to attack or disparage others," he said.
However, he added that social media it is not a substitute for face-to-face engagements, and MPs must establish personal bonds with residents and attend to their needs in person.
'Stand above any hint of favour or influence'
In his letter, PM Wong reiterated that a clean and incorruptible government is one of PAP's most precious asset and stressed that every MP must uphold the rigorous standards the party has set.