Following the first count of all the votes, including advance and overseas postal votes, the Alliance remained 297 votes shy of achieving a majority of votes cast.

According to preliminary results, the four centre-right Alliance parties received 2,929,771 votes, while the three centre-left parties of the Red-Green coalition received 2,591,827.

In addition, 338,241 ballots were case for the Sweden Democrats.

But a number of ballot counting irregularities have been revealed which could yet tip the election results.

In Värmland around 50 votes were classified as invalid for reasons that remain unclear. And when the municipality of Arvika, located in Värmland county, dropped off its ballots to the county administrative board in Karlstad, a stack of loose ballots which were declared invalid also turned up, along with a list of explanations for the nullifications.

However election official Gith Nilsson is critical of some of the explanations.

“Certain reasons are certainly correct there are a number which give me pause,” she told the TT news agency.

“For example, one of the reasons was that the ballot envelope wasn’t fully sealed, and I don’t think that’s sufficient reason to disqualify a ballot.”

The disqualified votes could potentially sway the final election results, as the Alliance missed a seat in the Värmland voting district by just seven votes.

“Because the municipality didn’t have them in the container, we can’t include them in the election results, forcing us to disqualify them because only ballots inside the container can be counted,” said Nilsson, who added she’s unsure what will happen next.

“There’s a possibility to contest the results, but then one has to turn to the Election Review Board (Valprövningsnämnden).”

The Review Board can nullify an election and arrange new elections if mistakes were made that are considered to have affected the outcome. Anyone wishing to appeal something about the Riksdag vote has ten days to file a complaint with the Board.

Ballot counting issues have also occurred in other locations around Sweden, according to the Expressen newspaper.

Among them include 200 uncounted advance ballots in Halmstad municipality in western Sweden.

“There were approximately 200 advance ballots which we didn’t deliver to the right municipality at the right time,” Halmstad election committee chair Lars-Erik Blank told the newspaper.

The municipality was subsequently told by the county administrative board to not count 200 votes and instead file them away.

According to preliminary figures, Sweden’s voter participation increased to 84.6 percent in the 2010 elections, compared with 82 percent in 2006.