SINGAPORE - The Singapore Democratic Party (SDP) will not be contesting in Tanjong Pagar GRC in the upcoming polls.

Party activist Paul Tambyah told reporters on Thursday night: "Many people in Tanjong Pagar are very keen to vote but at the same time there are many other parties that have expressed interest."

SDP chief Chee Soon Juan said on Sunday the party would field candidates in the same four constituencies it stood in 2011 - Yuhua and Bukit Panjang SMCs and Sembawang and Holland-Bukit Timah GRCs - as well as Bukit Batok SMC and Marsiling-Yew Tee GRC.

Earlier this year, the SDP also said it was considering whether to stand in other constituencies, including Tanjong Pagar GRC, where the Singaporeans First party and the Democratic Progressive Party have also expressed interest in contesting.

Explaining the party's decision to not stand in Tanjong Pagar, Professor Tambyah said: "We owe it to the areas that we contested in 2011 to come back. So many people supported us, close to 40 per cent in Holland-Bukit Timah supported us, so it's just going to take a little bit more to bring us over the edge."

The professor and infectious diseases specialist at the National University of Singapore's medical school was among 30 SDP activists visiting blocks near Senja LRT, which falls under Holland-Bukit Timah GRC, on Thursday night to meet residents and share their plans for the coming election. Dr Chee was also part of the team.

The party got 39.9 percent of the vote in Holland-Bukit Timah GRC in the last election.

Opposition parties plan to meet on Monday to discuss the constituencies they will contest in, in a bid to contest every seat as well as avoid three-cornered fights that are seen as advantageous to the ruling People's Action Party (PAP).

"It will be important for everybody to understand how to give Singaporeans an alternative, to provide a check and balance, and perhaps even to ensure we deny the PAP a two-thirds majority," said Prof Tambyah.

But when asked what new candidates the party would be fielding, he would say: "You can wait and see."