Stockholm (AFP) - The far-right Sweden Democrats party on Saturday demanded that the prime minister and finance minister apologise for calling it "neo-fascist".

"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, the TT news agency reported.

Social-Democrat Prime Minister Stefan Lofven wrote in an op-ed published in the Dagens Nyheter daily on Saturday: "The Sweden Democrats are a neo-fascist party... that respects neither the differences between people nor Sweden's democratic institutions."

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

Loefven, in office for just two months, had called the March 22 election on Wednesday after the Sweden Democrats, who oppose his liberal immigration policies, refused to back his budget in parliament.

The snap polls are the first Sweden has seen in half a century.

The Sweden Democrats have already announced that they intend to turn the election into a "referendum on immigration".

The Sweden Democrats, with roots in the country's most radical extreme right, entered parliament in 2010 with the ambition of curbing Sweden's generous policy on immigration and refugees.

The party became Sweden's third-biggest in September general elections with 12.9 percent of the votes and 49 of the 349 seats in parliament.

All seven parties in parliament refuse to take on the Sweden Democrats as allies, however.