The People's Action Party (PAP) said it was "disappointed but not surprised" at the Singapore Democratic Party (SDP) and its leader Chee Soon Juan, after the opposition party stood by its claim to have pressured the ruling party into scrapping a plan to raise the population to 10 million.
"We are disappointed that Dr Chee and the SDP have dug their heels in, repeated their falsehoods and refused to apologise to Singaporeans for misleading them," the ruling party said. "Disappointed but not surprised, for we knew Dr Chee has not changed, cannot change and will never change."
The strongly worded statement comes after two days of exchanges between leaders of both parties on the issue that emerged during a televised debate on Wednesday night.
During the debate, Dr Chee claimed that Deputy Prime Minister Heng Swee Keat had "toyed with the idea" of raising Singapore's population to 10 million.
Foreign Minister Vivian Balakrishnan, who was representing PAP at the debate, said the claim was false.
Mr Heng also responded in a Facebook post the next day, saying he had not said the country should plan to raise its population to 10 million or mentioned the number.
The National Population and Talent Division also made clear that the Government has not proposed, planned or targeted for Singapore to increase its population to 10 million.
The population projection was suggested by Mr Liu Thai Ker, the former chief executive of the Housing Board and the Urban Redevelopment Authority, in a 2013 public forum, where he argued a 10 million population was necessary for Singapore to remain sustainable in the long term.
At a forum at Nanyang Technological University last year, Mr Heng was asked about Singapore's Population White Paper.
Responding to the question, Mr Heng said Mr Liu had publicly said Singapore should go for a higher population number.
Mr Heng also said the population number is not just about the physical space but also the social space and sense of togetherness. Mr Heng did not mention the figure.
Despite the clarification, the SDP, which is asking voters to reject a population of 10 million, has responded by claiming victory on that count.
Yesterday, the PAP characterised the SDP's response like this: "A simple analogy will explain Dr Chee's mendacity. Imagine this.
"Dr Chee claims you said you want to beat up your spouse. You deny it, and show proof that you neither said this nor have beaten your spouse. Instead of apologising, Dr Chee says: 'Victory! I extracted a promise from you that you will never beat your spouse.'"
The PAP also criticised SDP chairman Paul Tambyah, who yesterday repeated the assertion that the SDP had secured a pledge from the PAP on the population issue: "We are disappointed and surprised Dr Paul Tambyah, the SDP's chairman, has joined his chief in this charade. We thought he was a better man."
It then said opposition leaders like Workers' Party chief Pritam Singh had "opportunistically jumped into the fray", referring to Mr Singh's remarks yesterday when he asked why the Government could not have declared sooner that the population would be below 6.9 million in 2030.
"It is baffling that Mr Singh should ask this question," said the PAP. "During the Committee of Supply (debate) in February 2018, Minister Josephine Teo had said that our population would be significantly below 6.9 million in 2030.
"She repeated this in the Committee of Supply (debate) in February this year. Was the leader of the opposition not scrutinising the minister's statements?"
Separately yesterday, DPM Heng said that spreading falsehoods as Dr Chee has done is "not the right kind of politics".
"Singaporeans can judge whether you are saying something serious or you are just spreading statements like this with no basis whatsoever," Mr Heng told reporters on the sidelines of a walkabout in East Coast GRC.
"This is not the right kind of politics. I think we must be sincere and honest in seeking to serve our people."
Mr Heng, who was accompanied on the walkabout yesterday by retiring East Coast GRC MP Lee Yi Shyan and new face Tan Kiat How, told reporters that many businesses have done well overseas because Singaporeans are known to have integrity.
"So we must keep honesty and integrity in our system, and we must expect that of all candidates."
Mr Heng also pointed out that Singapore is facing major challenges with the Covid-19 pandemic and global economic downturn.
"Let's not get distracted, let's focus on the key issues at hand," he said.
"And let's see how we can create a better life for all Singaporeans. This is the core issue of this election."