Since their election defeat in 2011, opposition politicians Yee Jenn Jong and Jeannette Chong-Aruldoss have continued to walk the ground in constituencies they contested, hoping for another bite at the cherry.

Only one of them will get their wish after the Electoral Boundaries Review Committee released its report yesterday - widely anticipated by opposition parties so they can firm up their election plans.

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

Mr Yee, a Workers' Party (WP) Non-Constituency MP in Parliament, said yesterday that he was "highly disappointed" as he had been visiting Joo Chiat residents every week for the last four years.

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

He is "open to all possibilities" on where to stand in the next general election now that his single-seat stomping ground is gone.

There was no such uncertainty for Mrs Chong-Aruldoss. Within an hour of the release of the boundaries report, she had changed her Facebook page cover photo to the Singapore People's Party (SPP) symbol accompanied by the words "Jeanette for Mountbatten".

She stood there in 2011 under the National Solidarity Party (NSP) banner but moved 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.

Yesterday, opposition parties moved to absorb the report's implications and to put their mark on newly demarcated constituencies.

Several criticised the retention of six-member GRCs, and said 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 hoped to see a sizeable drop in the 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 said the party was "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, three-member GRCs would serve the same purpose just as well.

The party was eyeing the Whampoa single-seat ward. Now that it is no longer on the electoral map, Mr Goh may shift his attention to the new 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. He said his party has been walking the ground regularly since the 2011 GE.

"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.

Singapore Democratic Alliance (SDA) chief Desmond Lim was glad the six-member Pasir Ris-Punggol GRC, which his party contested in 2011 and plans to do so again, has been left largely untouched.

"If there was a major change, our efforts over the last four years would have gone down the drain," he said.

And although the SDA previously hosted meetings among opposition parties in 2006 and 2011 to discuss strategy and how to avoid multi-cornered fights, he said he had no plans to do so this time.

NSP president Sebastian Teo also said there were no immediate plans for the 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."

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 WP plans to do there as well."

The parties also saw the report's release as a sign that an election 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."