Workers' Party (WP) Non-Constituency MP Leon Perera yesterday called on the Government to educate new citizens that their votes are secret.
He said he had met several new citizens who said they would lose their citizenship if they did not vote for the People's Action Party (PAP).
One was an older, highly educated man who feared it would happen if he voted for the WP.
Mr Perera, who spoke during the debate on the Prime Minister's Office budget yesterday, was rebutted by two ministers.
Senior Minister of State Josephine Teo, who is in charge of population matters, including new citizens, said the issue of electoral fraud had not been prominent in any election.
Also, most citizens believe in the secrecy of their vote, she added.
She noted that the vast majority of new adult citizens have lived in Singapore for at least five years before naturalisation, and would typically have witnessed at least one election before becoming citizens.
Mrs Teo also said that from an early age, she saw TV advertisements during elections assuring people that their votes are secret.
"I don't know of many other citizens who doubt that. I urge the Member not to be overly worried."
Mr Perera suggested that a paragraph on vote secrecy be added to the handbook given to new citizens.
Deputy Prime Minister Teo Chee Hean pointed out that the PAP and the Government had always said the vote is secret. He said the ones saying the vote was not secret was the WP. "Until they discovered it was not such a good idea... they now go out to tell people your vote is secret. For which we're grateful.
"The Government has been saying that all along and we're glad that you agree," said Mr Teo.