The hot seats to watch this election
The Workers' Party (WP) wrested the five-member GRC from the ruling party at the 2011 polls in a historic win. In the last election, the WP was able to cling on with 50.95 per cent of the vote against 49.05 per cent for the People's Action Party (PAP) team led by veteran MP Yeo Guat Kwang.
The GRC - home to 151,007 voters - is likely to provide the hottest contest between the ruling party and the WP.
The issue of the WP leaders' management of the town council's finances could play a role in swaying voters.
Last October, the High Court found that WP chief Pritam Singh and his fellow Aljunied GRC MPs Sylvia Lim and Low Thia Khiang had breached their duties towards the Aljunied-Hougang Town Council, which is said to have made millions in improper payments under their watch. They have appealed the ruling and the matter is still unresolved.
The three were part of the team - with Mr Chen Show Mao and Mr Faisal Manap - that won in 2011 and 2015.
The slate in Aljunied is likely to see changes, with rumours that Mr Chen is stepping down and uncertainty over Mr Low's candidacy after he suffered a fall.
Mr Low is recovering, the party said, but sources say he was thinking of retiring even before his accident.
EAST COAST GRC
The WP has faced off here against the PAP in the last three general elections, and is expected to put up a fight again this year.
For the PAP, it is unclear who will lead the charge. Two incumbent MPs on the team, Mr Lim Swee Say and Mr Lee Yi Shyan, are expected to step down.
The latest electoral boundary changes place Fengshan back in the GRC, after it was carved out as a single-member constituency in the last election.
In 2015, the PAP held East Coast with 60.7 per cent of the vote - their worst-performing GRC in that election. In Fengshan, PAP backbencher Cheryl Chan fended off a challenge from WP candidate Dennis Tan, winning 57.5 per cent of the vote.
The new GRC has been formed by taking the Sengkang Central ward from Pasir Ris-Punggol GRC and combining it with Punggol East SMC and part of Sengkang West SMC. It has 120,166 voters.
The PAP won Punggol East by a slim margin in 2015, and the WP has continued to walk the ground in the areas now under Sengkang GRC.
In the last election, PAP's Dr Lam Pin Min defeated his WP opponent Koh Choong Yong in Sengkang West with 62.1 per cent of the vote.
Over in Punggol East, PAP stalwart Charles Chong in 2015 took the SMC from Ms Lee Li Lian of the WP, with 51.76 per cent of the vote.
Ms Lee, who won the SMC in a 2013 by-election, is expected to lead a WP team in Sengkang GRC.
The PAP team in Sengkang will likely consist of labour chief Ng Chee Meng, Senior Minister of State for Transport and Health Lam Pin Min, Senior Parliamentary Secretary for Home Affairs and Health Amrin Amin, and lawyer Raymond Lye.
WEST COAST GRC
Former PAP MP Tan Cheng Bock returns to his old stomping ground as an opposition candidate for the first time, making the battle for West Coast GRC one to watch.
Dr Tan is a well-known face here. He is expected to lead a team from the Progress Singapore Party (PSP).
West Coast has been bumped up to a five-member GRC with 146,251 voters, and it gave the PAP a 78.57 per cent win in the 2015 election.
The PSP team will include Ms Hazel Poa and political newcomers Jeffrey Khoo and Nadarajah Loganathan.
Communications and Information Minister S. Iswaran, former minister Lim Hng Kiang, Mr Patrick Tay and Ms Foo Mee Har are part of the PAP team in West Coast GRC.
KEBUN BARU SMC
Signs point to a three-cornered fight between PAP, PSP and Democratic Progressive Party in Kebun Baru SMC, which has been carved out of Nee Soon GRC. Kebun Baru has 22,653 voters.
The PAP's Henry Kwek and PSP chief Tan Cheng Bock visited the Mayflower Market and Food Centre last week.
With Dr Tan were PSP central executive committee member Michael Chua and three PSP members - chartered accountant Kayla Low, former SingFirst chairman Ang Yong Guan and online news portal The Independent Singapore's former publisher Kumaran Pillai.
- Marymount SMC, Punggol West SMC and Yio Chu Kang SMC could also see keenly contested tussles.