SINGAPORE - Both are lawyers in a face-off. Their battleground, though, is not the courtroom but the single-seat ward of Mountbatten.

And their challenge is to win the support of the large number of voters who live in the constituency's condominiums.

In one corner of the ring is the People's Action Party (PAP) candidate Lim Biow Chuan, a 52-year-old partner at a small law firm who is defending his Mountbatten seat.

During the 2011 General Election, he beat National Solidarity Party (NSP) candidate Jeannette Chong-Aruldoss with 58.6 per cent of the vote.

Now, Mrs Chong-Aruldoss, also 52, is back for a rematch under the Singapore People's Party (SPP) colours.

That, itself, has added an interesting twist to the contest.

Many have noticed that SPP is her third party. She started out as a member of the Reform Party (RP) in 2010, before she joined NSP in March 2011 and became its secretary-general two years later.

Last year, she made a bid for the party's presidency, but lost by a majority vote.

Perceptions of her as a party-hopper do not faze her, she said. She meets them head on.

"I want you to know that I worked very hard at NSP; I would probably even have done more work for Mountbatten if not for the fact that I had to spend a lot of time serving out my responsibilities.

"I wanted it to be a party active in the political landscape and not just during election season," she said.

"When I was not endorsed, I could not carry on," she added.

She has now parked her allegiance with SPP, where she said she has the support of Mr Chiam See Tong - the party's first elected MP - and his wife Lina. But the battleground where she returns to face her old rival presents a logistical challenge like no other.

At the heart of their battle are the 102 condos and private apartment blocks in Mountbatten where about 42 per cent of its 24,143 voters live. This translates to about 10,000 voters.

Nationwide, only 12.2 per cent of the residential population live in condos and apartments.

Elsewhere in Mountbatten, about 2,000 voters (8 per cent) live in landed properties and 12,000 (50 per cent) in Housing Board flats.

"These condos are difficult to get into," said Mr Lim.

At the mid-point of the nine-day election campaign on Saturday, Mr Lim said had visited 28 of the 56 blocks of HDB flats in his ward.

But he was not able to visit a single condo because the residents' committees frown on political activities in their compounds.

He had to resort to standing with his volunteers in Tanjong Rhu Road and Meyer Road to distribute fliers to residents walking out of the condos instead. "In 2011, we were even chased away by security guards when we were standing in the public roads," he said.

Mrs Chong-Aruldoss also finds walkabouts at condos more daunting than those at HDB blocks.

"I've got a feeling this is going to be difficult! Tanjong Rhu's much more spread out than the main population catchments, so we've got to fan out across the estate," she said on Facebook last week on her walkabout in Tanjong Rhu.

Besides walking the ground, Mrs Chong-Aruldoss is relying on social media to reach out to voters, including those who live in condos. She set up a Facebook page Jeannette for Mountbatten and updates it regularly. She wrote: "While social media alone's not going to win an election, I find it a great way to share what it's like being a candidate with you guys."

The co-founder of Archilex Law Corporation is funding her own campaign. "The last thing I want to do is to consume Mrs Chiam's resources," she said.

Mrs Chong-Aruldoss also has to take on an incumbent who has relentlessly pounded the streets.

Mr Lim said that in the last four years, he has visited more than 40 condos in the ward after the residents invited him for dialogues. But he noted he was there as an adviser of the grassroots organisations affiliated to the People's Association, not as an MP to canvass votes.

Mrs Chong-Aruldoss feels it is unfair that her opponent can use his position as a grassroots leader to interact with so many residents, while she could not get access to them at all.

"I am not against the grassroots leaders who have altruistic intentions," she said. "It's the system I'm up against."

Despite Mr Lim's efforts, there are 10,000 or so condo voters that he has not been able to reach in this campaign. To convince them, he said, he will have to rely on the record of his work in the last five years.

In the House, the chairman of the Government Parliamentary Committee for Education has sought to reduce the stress on students. As president of the Consumers Association of Singapore, he has also championed the "Lemon Law" and gone after dishonest retailers.

In Mountbatten, he has built fitness corners, playgrounds and covered walkways, improvements that also benefit private home owners.

Mrs Chong-Aruldoss is campaigning on enhancing social mobility, preserving Mountbatten's heritage, keeping food costs in the area under control and having a professionally-run town council if elected.

She also points to her deep personal connection with Mountbatten. It was where she lived in the first eight years of her life; it is also where she and her husband first set up home when they got married in 1989.

And while she may not have met as many residents as Mr Lim over the past four years, she is heartened that some of them have made the effort to reach out to her.

Some days back, she was about to tuck into her plate of chicken rice at Jalan Batu hawker centre when a man suddenly plonked himself on a seat next to her.

The retired banker living in Meyer Road had found out she was doing a walkabout in Kampung Arang and wanted a copy of her manifesto. He also wanted to assess her.

"I want to make sure that whoever speaks on my behalf in Parliament is not an idiot," he said.

For this campaign, Mrs Chong-Aruldoss held a rally on Sunday, while Mr Lim is holding a rally tonight at a sports field at the Singapore Sports Hub.

The battle, meanwhile, is also being fought on many fronts - from the personalities of the candidates to the upgrading of the estate.

Mr Lim said he has walked each of the 56 blocks of HDB flats in the constituency at least twice since 2011, keeping an eye on the state of the roads and drains and other problems flagged by residents.

Retired businessman Kho Kok Chew, 73, who lives at Block 6, Jalan Batu off Mountbatten Road, said that Mr Lim is a common sight in his estate: "He is always walking around the HDB blocks."

During a three-hour walkabout at markets and hawker centres on Saturday, The Straits Times saw elderly residents going up to Mr Lim and peppering him with questions such as whether their children who are overseas can vote and asking for lifts to be built at an overhead bridge. An old woman even asked for help retrieving a seniors' discount card that she said FairPrice retained and threw away.

At the Kallang Estate Market, a young resident in her 30s walked up to Mr Lim and showed him a photo of a clogged drain near the market. Mr Lim, who is the Marine Parade Town Council chairman, waved at a volunteer to take down the details. "I will sort it out, don't worry," he said.

The resident, who would give her name only as Ms Ng, told The Straits Times: "I will be keeping a lookout to see whether the clogged drain is cleared."

As for Mrs Chong-Aruldoss, one thing she knows is that she would dearly love to be in the position that Mr Lim has enjoyed over the past four years or so - in Parliament.

"Because any man outside the House will not be very effective. You can be a blogger, you can write letters to the Forum, but you have a voice only if you've been elected."

Mr Lim would not be drawn into commenting on his chances on Friday. "The decision really lies in the voters' hands," he said.