Workers' Party (WP) chairman Sylvia Lim yesterday said she has initiated talks with the National Solidarity Party (NSP) over their overlapping interest in contesting Marine Parade GRC and the MacPherson single-seat ward.
"We do recognise that the NSP contested there the last general election," she said.
The WP, which has the largest opposition presence in Parliament, was one of seven opposition parties on constituency visits yesterday, during which their leaders reiterated their commitment to avoid three-cornered contests.
NSP acting secretary-general Hazel Poa agreed that it would be in the party's interest to work out an arrangement with WP.
Yet even as leaders appeared to strike a conciliatory tone, the parties continued to lay down markers in constituencies they are keen on contesting.
For one thing, the WP has been doing daily house visits in Marine Parade GRC for the past week.
Ms Poa, on the other hand, was on a walkabout at a market in MacPherson yesterday.
And Singapore People's Party (SPP) Non-Constituency MP Lina Chiam told reporters yesterday: "We are open to compromise but SPP will be in Potong Pasir and Bishan-Toa Payoh regardless of who else runs here."
This puts her party on a collision course with the Democratic Progressive Party's (DPP) Benjamin Pwee, who has been equally unwavering in his public statements about his party standing in both constituencies. He had contested Bishan-Toa Payoh GRC as part of an SPP team in 2011.
Tanjong Pagar GRC, which was last contested in 1988 when it was still a single-seat ward, is also being eyed by DPP and Singaporeans First (SingFirst) party.
Mr Pwee has raised the possibility of pooling the two parties' best candidates in a combined slate.
But when asked about this plan yesterday, SingFirst secretary-general Tan Jee Say said: "You know, thanks very much for the offer but we have our own candidates."
He added: "We have more than enough people for more than one GRC. We have no need to join with anyone, but that doesn't rule out joining forces."
These remarks came as party leaders prepare to hunker down tonight at a meeting hosted by the NSP to discuss election strategy and avoid three-cornered fights.
Such contests were kept to a minimum in 2011, when there was just one - in Punggol East involving the People's Action Party, Singapore Democratic Alliance and WP.
Opposition party leaders have been speaking about the need for unity but it has often proven elusive in recent years as the opposition has splintered into nine separate entities since the 2011 elections.
If all nine parties contest the coming polls as is expected, it will be the highest number since independence. But political observers said it remains to be seen if they can overcome the differences that pulled them apart in the first place, and present a united front this time.
And even as the parties seek to reach an understanding, internal disagreements could still pose problems.
The DPP told The Straits Times on Saturday that it was withdrawing from the newly created Fengshan single-seat ward and redeploying party veteran Seow Khee Leng to Tanjong Pagar GRC instead.
But Mr Seow said during a walkabout in Redhill yesterday that he remained keen to stand in Fengshan.
The WP's Ms Lim, who was unaware of these developments, said: "Mr Seow was a former WP member and candidate and (WP chief) Mr Low (Thia Khiang) and I know him personally. So we intend to meet him individually to try to resolve the issue of Fengshan."
Mr Pwee yesterday issued a statement saying the DPP was heartened by Ms Lim's "openness to talk and discuss a joint strategy for Fengshan based on their longtime friendship with DPP veteran Mr Seow" .