Two new Non-Constituency MPs (NCMPs) of the Workers' Party (WP) got their first taste of verbal sparring in Parliament yesterday, as they sought to highlight the potential negative effects of having one party in power for more than 50 years.

Mr Leon Perera argued that greater political diversity was needed for robust debate on policies, while Mr Dennis Tan said the governance of national institutions must be strengthened.

Veteran People's Action Party (PAP) MPs, however, took issue with the points they raised.

Mr Cedric Foo (Pioneer) said the Government had made constitutional guarantees of alternative voices in Parliament, while Mr Seah Kian Peng (Marine Parade GRC) indicated that the WP should take a look at its own town council if it was serious about the proper management of public bodies.

Mr Perera said some had interpreted the outcome of last year's general election - which the PAP won with 69.9 per cent of the votes - as a sign that "we were one united people".

But "casting the election result as a badge of national unity is deeply unhelpful" as it suggests that "what unites us as Singaporeans is our support for one political party".

Instead, unity comes when disagreeing parties can still recognise each other as Singaporeans, he said.

"We must learn to agree to disagree without branding one who disagrees with us as our enemy or as someone who has disrespected us," he said. "Let us debate and disagree but remain united as Singaporeans. That is real unity worth fighting for."

Mr Perera also said "the non-existence of any viable alternative party other than the ruling party" was a "danger facing Singapore's political landscape in the long term".

Mr Foo countered: "Mr Perera bemoans the low number of opposition MPs in this House, yet in the same breath he calls for open contest and for more democracy."

He pointed out that every seat in the last election was contested and the results were "the outcome of an open contest and I hope he and his party will respect the outcome".

Mr Foo also noted the Government had introduced the Nominated MP and NCMP schemes to provide for non-partisan voices and a minimum number of opposition members. "In fact, the presence of Mr Perera as an NCMP himself was a creation of the PAP Government... and I know of no government that guarantees there will be at least nine opposition members in Parliament."

Mr Tan, in his speech, said national institutions, including the civil service and statutory boards, must be further strengthened. "The independence and political neutrality of the civil service and statutory boards must be fiercely maintained so that Singaporeans will always have complete confidence in the non-partisan nature of these institutions."

He reiterated his party's call for a Freedom of Information Act and an "independent office of ombudsman" to investigate alleged wrongdoing by public servants.

Singapore must also promote social justice and take care of the less privileged, Mr Tan added.

Mr Seah said he totally agreed that "we should all embrace" strengthening of governance in organisations. It matters, be it a listed company, sports association or religious institution. "I dare say also in the town council," he added, alluding to financial and governance lapses in the WP-run Aljunied-Hougang Town Council.

Mr Seah also said the PAP "takes great pains to ensure" there is social mobility in Singapore. Many ministers, including the Prime Minister, have stressed that "we should leave no one behind".