The wooing of Holland-Bukit Timah GRC voters has heated up, with Environment and Water Resources Minister Vivian Balakrishnan and Singapore Democratic Party (SDP) leader Chee Soon Juan clashing over the policy proposals of the opposition party.

Such policies - "copied" from parts of the world where they have failed - would set Singapore "on the road to Greece", Dr Balakrishnan said, referring to the debt-stricken European country.

Dr Chee, in his rebuttal, said the People's Action Party's (PAP) policies sometimes imitate the SDP's in piecemeal fashion after seeing people clamour for them in previous elections.

He gave the example of the progressive wage model the Government launched in 2012, which ties the pay rises of low-wage workers to training.

"(They) call it by another name, but it's still the minimum wage for selected industries," he said.

Dr Chee added that SDP's proposed minimum wage will be universal, whereas the Government's existing model applies to cleaners and security guards at the moment.

His teammate, medical professor Paul Tambyah, criticised Dr Balakrishnan's remark that funding the policies would lead to ruin, saying it was a "red herring".

Citing the SDP's healthcare policy, he said: "Healthcare is actually essential to the defence of Singapore. The amount we propose reducing the defence budget (by) is minuscule... it would still leave Singapore's defence budget as far in excess of all the Asean countries put together."

The Greek crisis, he added, was a case of its government's "uncontrolled overspending" whereas SDP is pushing for a reallocation of Singapore's defence budget to invest in healthcare reform.

The exchange between the two rival teams in the past two days was sparked by Dr Balakrishnan's comment after nominations closed on Tuesday.

The SDP response came after a walkabout yesterday in Holland- Bukit Timah GRC.

But Dr Balakrishnan did not let the matter rest. In a sharp rejoinder last night, he pressed Dr Chee for specific details of his tax and expenditure plans.

"Will Dr Chee Soon Juan declare the total bill he intends to spend on all his plans? What taxes will Dr Chee Soon Juan raise and from whom?" he wrote in a Facebook post filled with what he termed "awkward questions".

Referring to the SDP's plans to cut $5.75 billion from the current defence budget, he asked: "Is it responsible for Dr Chee and his team to ask for such a huge cut in defence spending, given the current global and regional climate?"

He said Dr Chee's policies, which he termed "cut and paste" and "irresponsible", would "put our national security at risk" and result in much higher taxes and "higher national debts for our children".

Dr Balakrishnan also took issue with the SDP's claims that its healthcare policy is modelled on the French system.

"Will Dr Chee tell Singaporeans what are the French rates for personal income tax, corporate tax and GST (known as VAT, or value added tax, in France)?"

Other PAP members have also criticised Dr Chee, who last contested in the 2001 General Election.

Minister of State Sim Ann, who is on Dr Balakrishnan's GRC team, highlighted Dr Chee's dispute with his former mentor, veteran politician Chiam See Tong.

She had said, after nominations closed on Tuesday, that Dr Chee had "kicked" Mr Chiam out of the SDP in 1993.

The party had said then that Mr Chiam resigned on his own accord.

Dr Chee's past was also raised at a TV forum on Tuesday night.

Minister for Culture, Community and Youth Lawrence Wong, the PAP's anchor minister in Marsiling-Yew Tee GRC, noted that Dr Chee gave false information in 1996 to a parliamentary committee on verifying healthcare subsidies of polyclinics and public hospitals.

When asked about it yesterday, Dr Chee said he found the highlighting of his past "tragic".

"The PAP is incapable of focusing on issues. They know they're weak on that. They know Singaporeans are very unhappy with their policies. So what do they do? They throw up all these distractions to make sure they don't then have to debate us on these policies."