One in three voters have not yet chosen who to vote for, according to a poll for Sveriges Radio on Thursday.
Among young people that figure rises to almost two in three.
The figures follow a campaign during which youth unemployment has been a hot topic.
Fredrik Reindfeldt's Moderate Party is hoping to attract more young voters. Photo: TT
The Swedish economy and its AAA credit rating might be envied by most European countries, but unemployment among people aged 15 to 24 has been oscillating between 20 and 25 percent over the past years — about three times higher than overall joblessness.
Sweden's general election campaign has even spilled over into Norway as political rivals pursue votes among the tens of thousands of mostly young Swedes emigrating to find work.
Close to full employment, Norway is seeking foreign workers to meet labour shortages, and many Swedish waiters, nurses, dentists, engineers are crossing the border.
Jimmie Åkesson has been targeting Swedes working in Norway. Photo: TT
Jimmie Åkesson, leader of the anti-immigration Sweden Democrats, has been campaigning in Oslo. He argues that the reason so many Swedes have to emigrate is that foreigners are taking their jobs back home.
"When Sweden grants twice as many residence permits as it creates jobs, that's what you get," he told news agency AFP.
However, Malin Sahlén, an economist who has written a book on the issue, believes that the reasons for the high unemployment are different.
She argues that low-qualification jobs are rare in Sweden's economy and that high protection of employees on permanent contracts make employers resort to hiring temporary workers, which tends to create frequent gaps of unemployment when those workers change position.
"According to Eurostat, 14 percent of the jobs in Europe are low-paid, and that figure is only 3 percent in Sweden," she said.
Meanwhile Thursday's party leader debate on TV4 ended in a brawl over nuclear power. In the final stages of the discussion, the Alliance party leaders questioned Social Democrat leader Stefan Löfven on how he intends to tackle the issue.
Even if you don't speak Swedish, take a look at the body language in this clip. Video: TV4
Löfven has previously spoken out in favour of retaining Sweden's nuclear power stations, but during the debate he would only speak broadly about offering a "future analysis" of the country's energy demands and the need for a Red-Green bloc agreement on the issue.
Centre Party leader Annie Lööf asked him to be more specific, producing a copy of a report by the Swedish Energy Agency and taking it over to him. He held his hand up in protest and appeared as if he was trying to push her away.
"This is just bickering. You can keep it there," said Löfven.
Their actions provoked a storm on social media, with some arguing that Lööf appeared immature and others slating Löfven for being too defensive.
On Friday Löfven sought to play down the incident.
"It was not a shove. I only pushed the paper, but was nothing serious," he told Swedish television.
He said he had previously read the report and said it was important to "debate" the issues included in it.
Annie Lööf told Swedish media that Löfven's actions suggested he could not effectively demonstrate "statesmanship".
Annie Lööf raised her profile during the election debate on Thursday. Photo: TT
On Saturday night there will be a final live television debate between Prime Minister Fredrik Reinfeldt who leads the Moderate Party and Social Democrat leader Stefan Löfven.
Carin Jämtin, party secretary for the opposition Social Democrats told Sveriges Radio there were still a lot of votes to play for before Sunday: "The last part of the election campaign is very important. We will knock on doors, take part in debates and talk with voters in other ways right up to the end of polling day," she told Sveriges Radio.
Per Nilsson, head of analysis for the ruling conservative Moderates says his party will also do what it can to attract the undecided voters: "It's not about targeting a specific part of the electorate with surgical precision", he told Swedish Radio, adding "we're going out with a broad message about how we want to make Sweden better together with our colleagues in the Alliance."
Elections take place on Sunday with voting closing at 8pm
The first exit polls are usually released once people have finished voting, but this year pollsters YouGov have announced that they will make a prediction at 4pm, a move that has caused controversy, with some commentators arguing the poll could influence those who have yet to vote by this point.
The Local will be blogging live throughout the night and you can follow us on Twitter @TheLocalSweden