A Swedish far-right party is demanding an apology, after the country's finance minister and prime minister branded them a "neo-fascist" organisation.

"It's remarkable that both a prime minister and a finance minister speak in this way and it calls for an apology to the Sweden Democrats party and to all voters," spokesman Bjorn Soder said at a party meeting, reports AFP.

Previously, Swedish prime-minister Stefan Lofven warned of the dangers posed by the party, that has campaigned on a strongly anti-immigration platform and has surged in popularity, becoming the third most popular party in Sweden.

"The Sweden Democrats are a neo-fascist party… that respects neither the differences between people nor Sweden's democratic institutions," said Lofven.

Finance Minister Magdalena Andersson said: "What we have here is a neo-fascist party which believes it must have a decisive influence and set the agenda in Swedish politics," she said.

On Wednesday, Loefven, who has only been in power for four months, was forced to call an election on 22 March 2015 after the Sweden Democrats refused to back his budget in parliament.

They are the first snap polls in Sweden in half a century, with the Sweden Democrats announcing that they intend to turn the elections into a "referendum on immigration".

In September's general election the Sweden Democrats gained 12.9% of the vote, and won 49 seats. A recent YouGov poll showed that the party now has the support of 17% of the electorate.

All seven of Sweden's parties refused top form an alliance with the party, which has its roots in the country's extreme right.

The party holds the balance of power in parliament, after both left and right-wing blocs failed to secure majority support.