SINGAPORE - Changes have been made to the boundaries of electoral constituencies ahead of the next general election.

One in five voters, or 19 per cent of voters, will find themselves in a new constituency, according to the report of the Electoral Boundaries Review Committee made public on Friday.

This figure is fewer than the 30 per cent of voters affected in the past boundary redelineation ahead of the 2011 General Election.

There are around 2.46 million eligible voters, up from 2.35 million in 2011.

The number of elected Members of Parliament will rise from the current 87 to 89.

There will also be 13 Single-Member Constituencies (SMCs) and 16 Group Representation Constituencies (GRCs), up from the current 12 SMCs and 15 GRCs.

Two SMCs have been absorbed into neighbouring GRCs: Joo Chiat will be part of Marine Parade GRC, while Whampoa will be part of Jalan Besar GRC.

Three new SMCs have been created from larger GRCs: Bukit Batok has been carved out of Jurong GRC, Fengshan out of East Coast GRC, and MacPherson out of Marine Parade GRC.

However, 10 of the existing 12 SMCs remain largely unchanged, with Sengkang West seeing several polling districts moved to neighbouring Ang Mo Kio GRC.

There will also be six four-MP GRCs, up from the current two.

They are Chua Chu Kang GRC, East Coast GRC, Holland-Bukit Timah GRC, and West Coast GRC, as well as new Jalan Besar GRC and Marsiling-Yew Tee GRC.

Jalan Besar GRC is largely made up of the existing Moulmein-Kallang GRC, as well as districts from existing Tanjong Pagar GRC and Whampoa SMC.

Marsiling-Yew Tee GRC is made up of polling districts from the existing Chua Chu Kang GRC and Sembawang GRC that have seen significant population growth in recent years.

There will also be eight five-MP GRCs, down from the current 11.

These eight GRCs are: Aljunied, Bishan-Toa Payoh, Jurong, Marine Parade, Nee Soon, Sembawang, Tampines and Tanjong Pagar GRCs.

Both Aljunied and Tampines GRCs remain unchanged.

Sembawang absorbs districts of neighbouring Nee Soon GRC, while Nee Soon GRC absorbs districts of neighbouring Ang Mo Kio GRC.

Bishan-Toa Payoh and Tanjong Pagar GRCs will incorporate neighbouring districts from Moulmein-Kallang GRC.

Meanwhile, the existing two six-MP GRCs remain: Ang Mo Kio and Pasir Ris-Punggol GRCs.

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Ang Mo Kio GRC, which is helmed by Prime Minister Lee Hsien Loong, will absorb districts from Pasir Ris-Punggol GRC as well as Sengkang West SMC that have seen population growth from new housing developments in recent years.

The release of the report comes less than two weeks after Prime Minister Lee Hsien Loong said in reply to questions in Parliament on July 13 that the committee had been formed two months ago.

While there is no fixed date for the election to be called after the report is made public, it has in previous elections taken as short as one day and as long as one month and 26 days.

Mr Lee also said he had entrusted the committee to have smaller GRCs, so as to reduce the average size of GRCs to below five, and to have at least 12 SMCs.

The release of the report is widely seen as a sign that the next general election, which must be held by January 2017, is round the corner, with People's Action Party activists as well as observers expecting it to take place as early as September.

With the committee's report out, the next stage in the lead-up to Polling Day is for Parliament to be dissolved and the writ of election issued. In 2001, this happened one day after the boundaries report was issued, and in 2011, one month and 26 days.

Nomination Day must take place no earlier than five days and no later than one month after the writ is issued. Nomination Day is the start of the campaign period, which is required by law to be a minimum of nine days.

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There is then a Cooling-Off Day, which falls on the eve of Polling Day when voters cast their ballots.

PM Lee, when announcing the formation of the Electoral Boundaries Review Committee in Parliament on July 13, had assured the House there would be time for everyone to digest the committee's report once it was published.

"To the maximum extent possible, we will make sure that there is enough time elapsed so that everybody can read the report, understand it and know where they stand before elections are called," he had said then. "But I don't think it is possible to say that we promise a certain minimum period, such as six months, because it depends very much on the exigencies of the situation and on when elections become necessary."

An earlier version of this story said one in six voters will be affected by the boundary changes. It should be one in five. The earlier calculation excluded voters in Moulmein-Kallang GRC who will move to the renamed Jalan Besar GRC.