As the clock wound down on the most unusual election campaign in memory, party leaders raced around the island, as well as online, to make their pitches and sway voters ahead of Cooling-off Day today.

The ruling People's Action Party (PAP) asked voters to soberly decide who they would trust to steer the nation out of the monumental Covid-19 crisis that is looming and will have to be dealt with in the years ahead.

The opposition parties repeated their calls to deny the PAP a sweeping majority or a "blank cheque" that would allow it to implement policies at will. They also offered to voice alternative views in Parliament.

The safe distancing measures imposed on account of the pandemic ensured that the campaign ended with leaders from different parties making their final pitches not through islandwide rallies, but over fireside chats on cyberspace.

Prime Minister Lee Hsien Loong noted at PAP's final e-rally last night that it was an unusual end to a general election campaign, but an appropriate one, given the immense challenge still ahead for the country.

"Normally, it is a moment of high emotion: You are rousing everybody to fever pitch, getting them ready to do battle and vote on Polling Day.

"But (at) this one, we are discussing - soberly, seriously, calmly - issues, priorities, challenges, solutions" to the challenges facing Singapore, and how to tackle them together as one people, he said.

"It is appropriate in this moment that we should be in this frame of mind - serious, collected, a little bit detached - but we know that this is a serious problem, and let's make the most rational, sensible thing we can do to get through," he added.

PAP leaders sought a strong mandate to tackle the crisis that has deepened geopolitical tensions, disrupted supply chains and even fractured some societies.

PM Lee said jobs and income security are at the top of most people's minds, given the bleak economic outlook caused by Covid-19.

"People are very practical, these are things on their minds, and really the things which any leader, any government of Singapore must now focus on, once the elections are over," he said.

PAP leaders said the world - whether friends, foes or investors - are watching if Singaporeans fully back a government with a proven track record or will exit the polls with society divided.

Opposition parties here, however, called on voters to deny the PAP a super majority, by giving them one-third of the 93 seats up for grabs.

Former Workers' Party chief Low Thia Khiang took to YouTube to urge voters to deny the PAP a two-thirds majority that would let it "implement policies at its sole discretion".

"With the economic uncertainty looming over us, should we bet all our chips on the ruling party and hope that we luck out... and they will take good care of people in need?" he asked.

"Or should we groom more opposition members with alternative suggestions and opinions to enter Parliament to provide a well-rounded discussion on policies?"

While cyberspace was the dominant medium of communication, parties also used other ways to cap off the nine days of campaigning. For instance, the Singapore Democratic Party's (SDP) 11 candidates for this election had a mega walkabout in all five of the constituencies the party is contesting in, with the help of a chartered bus.

This year's drastically altered campaign meant some parties were more confident of their chances than others.

Progress Singapore Party chief Tan Cheng Bock said he is optimistic his team will do well in West Coast GRC and that this election, with its safe distancing rules, offered him a different perspective compared with his previous electoral outings.

He said his message that the ruling party has lost its way will carry weight with voters.

But SDP chairman Paul Tambyah, who is contesting in Bukit Panjang SMC, said he was not optimistic about the opposition's chances in this election.

"Between the major parties together, if we get one-third, we can prevent a super majority in Parliament," said Professor Tambyah, who said the timing of the election put the opposition at a disadvantage. "Although, to be honest, that is wishful thinking. Because right now, it looks like a wipeout. So, all we are trying to do is survive."

But the race looks to have tightened in recent days in the key battleground seats in West Coast GRC and East Coast GRC, some political observers have suggested. Some of these hot seats could come down to the wire, they noted.

Today is Cooling-off Day, which means electioneering is prohibited.

But as politicians take a break and Singaporeans here appraise various parties' plans, the first ballots will be cast in overseas locations.

Voters in London, for instance, can cast their ballots from 3pm today.