SINGAPORE - Since their election defeats in 2011, opposition politicians Yee Jenn Jong and Jeannette Chong-Aruldoss have continued to walk the ground in the constituencies they contested, hoping for a second bite of the cherry.

But only one of them will get their wish now.

While the Mountbatten single-seat constituency, where Mrs Chong-Aruldoss took 41.4 per cent of the votes cast, remains on the electoral map, Joo Chiat - which Mr Yee lost by a mere 388 votes - has been absorbed by neighbouring Marine Parade GRC.

Mr Yee, who is a Workers' Party Non-Constituency MP, said several times on Friday that he was "highly disappointed" by the news as he has been visiting residents in Joo Chiat every week for the last four years.

"I really feel very bad for the Joo Chiat residents that I have spoken to... Even people who voted for the People's Action Party, they were also looking forward to another close fight."

He said that he is "open to all possibilities" about where to stand in the coming general election now that his old single-seat stomping ground is gone.

There was no such uncertainty for Mrs Chong-Aruldoss.

Within an hour of the release of the report by the Electoral Boundaries Review Committee, she changed her Facebook page's cover photo to the Singapore People's Party (SPP) symbol accompanied by the words "Jeanette for Mountbatten".

She contested the constituency in 2011 under the National Solidarity Party (NSP) banner but switched to the SPP in March.

"As I promised four years ago, I'll be back at the polls in GE 2015. I promise to work even harder to win the hearts and minds of Mountbatten," she wrote on her Facebook page.

Meanwhile, Mrs Lina Chiam of SPP said she will stand again in Potong Pasir SMC which has remained intact. "We are happy SPP is still given a chance to be able to contest in that SMC, and if elected to serve Potong Pasir residents again, as what Mr Chiam has done in the past 27 years," she said, referring to her husband and opposition veteran Chiam See Tong who was a long-time MP of the SMC.

In the last election in 2011, Mrs Chiam stood as a candidate in Potong Pasir but lost to PAP's Mr Sitoh Yih Pin by a razor-thin margin of 114 votes - or by less than 1 per cent of the ballots cast.

Mrs Chiam said SPP will also field candidates in Bishan-Toa Payoh GRC and Hong Kah North SMC. The party will announce at a later date whether to contest other constituencies.

The release of the committee's report on Friday had opposition parties scrambling to absorb its implications and stamp their mark on newly demarcated territories.

Several criticised the retention of six-member GRCs, and said that changes to reduce the size of GRCs did not go as far as they expected.

Democratic Progressive Party secretary-general Benjamin Pwee said: "We are sad to see the large six-man GRCs remain untouched. We also hoped to see a sizeable drop in number of GRCs and increase in SMCs, for candidates to fight on their own credibility, and not ride on the coat-tails of other MPs."

He added that the party remained "committed to standing in Bishan-Toa Payoh GRC", which Mr Pwee contested in 2011 on an SPP ticket.

Similarly, Mr Goh Meng Seng of the newly-registered People's Power Party said that if GRCs were meant to ensure minority representation, then three-member GRCs would serve the same purpose just as well.

The party was eyeing Whampoa single-seat constituency, but now that it has been removed from the electoral map, Mr Goh said he may have to shift his attention to the newly-created single-seat wards of Bukit Batok and Feng Shan.

Reform Party chief Kenneth Jeyaretnam is eyeing West Coast GRC, Ang Mo Kio GRC and the Radin Mas single seat constituency, and said his party has been walking the ground regularly since the 2011 general election.

"I think it is important to challenge the Prime Minister on his home turf of Ang Mo Kio and I am glad to see he is still hiding behind a six-member GRC because it shows he is afraid," he said.

However, Singapore Democratic Alliance chief Desmond Lim was glad that the six-member Pasir Ris-Punggol GRC has been left largely untouched.

"If there was a major change, our efforts over the last four years would have gone down the drain," said Mr Lim, whose party contested the GRC in 2011. He said the SDA will definitely stand in Pasir Ris-Punggol again.

And although the SDA previously hosted meetings among opposition parties in 2006 and 2011 to discuss where each would contest in order to avoid multi-cornered fights, Mr Lim said there were no plans to organise such a meeting this time around.

"I'm not in the position to mobilise the opposition parties to sit down and talk," he said.

The National Solidarity Party's president Sebastian Teo also confirmed there were no immediate plans for different parties to meet.

"Everybody needs to have their internal discussions before they can have a talk with the other parties. From past experience, the parties will have their internal discussion first and then meet with each other within one to two weeks," he said.

Mr Tan Jee Say of the Singaporeans First Party said the "general consensus among the opposition is that we want to avoid each other" to prevent multi-cornered fights.

"We are interested in Tampines and Marine Parade, but now that Marine Parade has absorbed Joo Chiat, we will have to see what the Workers' Party plans to do there as well."

The opposition parties also took the release of the boundaries report as a sign that the elections will likely be held in September.

Said Mr Pwee: "We suspect this will lead to the PAP calling for a snap election, within a month after National Day."

Agreeing, Mr Teo said: "I think it is quite certain that elections will be in September. The PAP won't give three to six months' grace from the boundary announcement."

Additional reporting by Goh Yan Han