Outgoing Prime Minister, Social Democrat Magdalena Andersson, hopes to keep her chair by relying on the left and the greens.
According to two exit polls, the left camp led by Social Democrat Prime Minister Magdalena Andersson would win between 49.8% and 50.6% of the vote, against 48% to 49.2% for the right-wing bloc. extreme right.
The extreme right of the Sweden Democrats (SD) would reach a new all-time high of between 20.5% and 21.3%, becoming for the first time the second party in the Nordic country, according to these two polls carried out for Swedish television SVT and TV4.
According to the poll by SVT, the left bloc would win a total of 176 seats, just above the absolute majority of 175, compared to 173 for the right-extreme right bloc.
These first tight estimates, which were expected, promise a long election night to confirm the winners of this election with an unprecedented scenario. Partial results are expected around 10 p.m., before near-final results late at night.
Never until these legislative elections had the traditional Swedish right, led by the conservative candidate for Prime Minister Ulf Kristersson, considered governing with the direct or indirect support of the SD.
Long pariah, the nationalist and anti-immigration party led by Jimmie Åkesson also won first place in the new right-wing bloc.
Jimmie Åkesson, leader of the Swedish Democrats
Sweden's first female head of government, Magdalena Andersson, has led a red-green package, to land a third straight four-year term for the left.
According to the two polls by SVT and TV4, the Social Democrats have, as expected, held their first place since the 1930s (29.3 to 29.7%). The conservatives of the Moderates would be only the third party, with 16 to 18.8%.
A victory for the right supported by the extreme right would mean a a new political era for Sweden, which is due to take over the rotating presidency of the European Union on January 1 and finalize its historic candidacy for NATO – backed also by the right.
Conversely, a victory for the left and a defeat for the new nationalist-conservative bloc would call into question the right's decision to draw closer to the SD.
Important immigration and serious problems with criminal gangs have fueled the party in recent years.
In the electoral district on the outskirts of Stockholm, SD activists were jubilant at the announcement of the first estimates, in waving their party flags, and the hope remains that the right will take advantage.
Now we have for the first time a real chance, a real possibility not just to be an opposition party, but also to be part of a new government that takes politics in a completely different direction, a reacted the number two of the party, Richard Jomshof, at the microphone of SVT.
A total of 349 seats are allocated proportionally to parties achieving at least 4%. To be invested, a Prime Minister must not have 175 votes or more against him, but not necessarily an absolute majority in his favour.
Sweden's membership in NATO is dividing the population, which has not hesitated to take to the streets to express its opposition.
The campaign has been dominated by themes likely to favor the right-wing opposition: crime and murderous gang settling, soaring fuel and electricity prices, integration problems…
But the solid popularity of Ms Andersson, whose trust rating exceeds that of her Tory rival Ulf Kristersson, and the bogeyman of the far right argued in favor of the left .
On the eve of the vote , the five polling institutes gave a very slight lead to the red-green camp.