The anchor minister of the short-lived Moulmein-Kallang GRC, Dr Yaacob Ibrahim, last night said he welcomed the resurrection of Jalan Besar GRC, which was unexpectedly wiped off the electoral map in the last general election.

Its revival will largely undo boundary changes made in 2011, reuniting wards that were scattered to Tanjong Pagar GRC and Moulmein-Kallang GRC.

It will also reabsorb its old Whampoa ward, which in the last election was carved out as a new single-seat constituency under Senior Minister of State in the Prime Minister's Office Heng Chee How.

"The neighbourhoods of the new Jalan Besar GRC (have) the same make-up as the old (one)... I welcome back the Jalan Besar name, and I believe many residents will too," said Dr Yaacob, whose Kolam Ayer ward is going back to the GRC.

"The name 'Jalan Besar' has been around for over 50 years, and many residents can identify the place with the name," he added in a Facebook post.

In the country's first general election in 1959, the single-seat Jalan Besar saw a fierce four-cornered fight that ended in victory for the People's Action Party (PAP).

It was reconstituted as a GRC in 1988, and has been keenly contested by opposition parties at every election save one.

Jalan Besar GRC's sudden dissolution in 2011 saw the birth of the five-man Moulmein-Kallang GRC, which will now vanish after just one election.

Moulmein-Kallang saw a fierce fight between the People's Action Party and the Workers' Party in that election, with the PAP polling 58 per cent of the vote and winning.

Now, three of the wards in that GRC - Kolam Ayer, Mr Edwin Tong's Jalan Besar and Ms Denise Phua's Kampong Glam - will once again become part of Jalan Besar GRC. So will Dr Lily Neo's Kreta Ayer-Kim Seng ward, which in 2011 joined Tanjong Pagar GRC.

The new four-man Jalan Besar GRC is the third-smallest of the 16 GRCs on the new electoral map, with an estimated 102,454 voters.

For first-term MP Edwin Tong, the revival brings with it mixed feelings. On the one hand, he has become attached to Moulmein-Kallang, but the Jalan Besar name "has history and heritage".

It also better represents the GRC's location, he added.

"When I say 'Moulmein-Kallang', people ask me, 'Wait, where is that? Is it in Moulmein? Is it in Kallang? What does that mean?' " recalled Mr Tong with a laugh.

The new Jalan Besar GRC will have a more uniform population profile, he and his fellow MP Denise Phua said.

Moulmein-Kallang GRC now includes Mr Lui Tuck Yew's Moulmein ward, which has a concentration of landed houses at one end, in areas such as Linden Drive. The new Jalan Besar GRC, however, will be largely made up of voters in public housing.

But for those in Moulmein ward, the boundary changes mean bitter parting. A bulk of the ward will wind up in Tanjong Pagar GRC, said Moulmein branch secretary Chua Lai Teck. But the rest will be split up between the Holland-Bukit Timah and Bishan-Toa Payoh GRCs.

"We've seen the transformation of Moulmein from a slum to a middle-class neighbourhood," said Mr Chua, who has served in the ward for over 30 years.

"Our grassroots leaders are quite upset. There's a very strong sense of identity here in Moulmein. It's like splitting up a family."

Mr Lui, who has been the ward's MP since 2006, said he would leave with a sense of sadness.

While he has some idea of possible plans for him in the future, "this is not quite the right time" to reveal them, he added.