Stockholm (AFP) - Sweden's far-right Sweden Democrats, which recently topped an opinion poll for the first time, want a referendum to be held on the country's generous immigration policy, its party leader said Saturday.

"It's time for a referendum in Sweden on our immigration policy," Jimmie Akesson told supporters who gathered to hear his annual summer speech.

His chances of obtaining a vote are however slim: parliament must vote on whether to hold a referendum, and only six have been held since 1922.

Sweden welcomed 80,000 refugees last year, shouldering the biggest burden in the EU as a proportion of its population of 9.7 million.

With a cradle-to-grave welfare state, a reputation for tolerance, and a healthy economy and job market, Sweden is a favoured destination for the record number of migrants fleeing conflicts, authoritarian regimes and poverty worldwide.

Akesson said Sweden's open-arms policy and generous benefits system were contributing to the tragedy unfolding in Europe today.

"What is it that makes people risk their lives and those of their children to come here? I dare say it is the other parties' lax policies that cause many of these tragic fates. That cause death," he said.

The Sweden Democrats, with roots in Sweden's most radical extreme right, entered parliament in 2010 with the ambition of curbing immigration.

They became the third-biggest party in 2014 general elections with 12.9 percent of votes and 49 of the 349 seats in parliament.

A Yougov poll published on August 20 credited the party with 25.2 percent of voter sympathy, making it the biggest party for the first time in a poll, ahead of Prime Minister Stefan Lofven's Social Democrats with 23.4 percent.

However, another poll published Saturday and conducted by the Novus institute, credited the Sweden Democrats with 18.6 percent and the Social Democrats with 25.8 percent.

All seven other parties in parliament refuse to take on the Sweden Democrats as allies, and have rejected their anti-immigration stance.

For them, immigrants are welcome workers for a country with an ageing population.