In the 2011 presidential election, some candidates made promises to Singaporeans that were beyond the constitutional functions of a president.

In particular, there was the tendency to view the office, mistakenly, "as an alternative source of executive policymaking power", said the elected presidency review commission.

It made the point when proposing that laws be introduced to ensure candidates do not mislead voters. The response falls outside its terms of reference, but the commission felt the issue was "sufficiently significant to warrant discussion or at least a brief mention".

While laws exist to stop those who wilfully interfere with free elections, they do not address the misinformation of the sort seen at the last election, it said.

Such misstatements "may have stemmed from a failure to understand the proper remit of the presidency and in particular, the tendency to see it, mistakenly, as an alternative source of executive policy- making power", it added.

To address this, the commission suggested enacting several laws.

One, requiring candidates to explicitly declare - for example, in their application form - that they understand the constitutional role of the president, before they would be issued a certificate of eligibility.

Two, the act of making promises incompatible with the office of president would be an offence.

For example, candidates who promise better public transport or wider healthcare coverage, or who pledge to oppose spending for such programmes, would be breaking the law.

The commission did not name anyone but a couple of 2011 candidates would have run foul of the proposed rules.

Former civil servant Tan Jee Say pitched a $60 billion National Regeneration Plan to build more hospitals and schools, while former NTUC Income chief executive Tan Kin Lian said he would introduce state pensions for the elderly.

Should its suggestions be accepted, "it would be difficult for candidates to claim that any breach was borne out of ignorance", the commission said.

It also wants a regime of sanctions to be imposed for breaching election rules.

These should include criminal sanctions, which the commission did not specify. In extreme cases, a candidate's certificate of eligibility would be revoked.

The commission also called for rules to temper the "divisiveness of the election process" and ensure campaigning "remains consistent with the role of the president as a symbol of national unity and which preserves the dignity associated with the highest office of the land".

To achieve the goal, it proposed restricting or excluding acts that may "inflame emotions, cause divisiveness or encourage invective".

It also suggested a prescribed "white list" of approved campaign methods, such as televised debates or speeches.

"It is not clear to the commission if the holding of rallies, for instance, is either necessary or helpful in this context," the report said.

MP and lawyer Vikram Nair welcomed the suggestions: "It's important for candidates to campaign responsibly, and not win votes on false promises."