Budapest (AFP) - Hungarians are poised to reject the EU's troubled refugee quota plan in a referendum on Sunday, as fiercely anti-migrant Prime Minister Viktor Orban rides a populist wave across the bloc.

Following are the main European populist parties that have stoked concerns about the continent's worst migrant crisis since World War II to boost their support and even enter government in some countries.

- 'Disgusting worms' -

- GERMANY: Chancellor Angela Merkel's Christian Democratic Union (CDU) suffered a stinging setback in state elections in Berlin on September 18 in a backlash against her "open-door" refugee policy.

Alternative for Germany (AfD) won seats in the regional parliament with 14 percent of the vote -- not far behind the CDU's 18 percent.

A recently elected Berlin deputy for the AfD reportedly called Syrian refugees "disgusting worms" and said asylum seekers were "parasites which are feeding off the German people".

Two weeks earlier, the AfD came ahead of the CDU in a northeastern regional poll. It now has seats in 10 out of Germany's 16 regional parliaments.

- AUSTRIA: The Freedom Party (FPOe) narrowly missed winning a May 22 presidential election. This would have made Norbert Hofer Europe's first far-right elected head of state since 1945.

However, Hofer will have another stab at winning the election on December 4 after the country's highest court annulled the May result due to procedural irregularities. He has said Islam "has no place in Austria".

Austria was located on the so-called Balkan migrant route, which saw hundreds of thousands of people, many fleeing the Syrian war, trek up from Greece towards northern Europe last year.

- SLOVAKIA: In March, the People's Party Our Slovakia won 14 seats in the country's 150-seat parliament, four years after it was founded on a platform hostile to the Roma minority, the EU and NATO. Party leader Marian Kotleba has been branded a neo-Nazi by opponents.

Populism has spread into mainstream parties too, with Prime Minister Robert Fico taking one of the EU's tougher stances on immigration. He has branded the migrant crisis an "onslaught" and called EU migrant policy "ritual suicide".

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- Anti-migrant fences -

- HUNGARY: Orban, head of the right-wing Fidesz party, has organised the October 2 referendum on migrant relocation under an EU quota plan.

In late 2015, Hungary built fences along its borders with Serbia and Croatia to stem the massive tide of migrants. Other countries in the Balkans then followed suit.

Those migrants who do sneak through into Hungary suffer illegal border pushbacks and unlawful detention, Amnesty International said Tuesday.

Orban has called immigration "poison" and has said that "every single migrant poses a public security and terror risk".

- POLAND: The Law and Justice (PiS) party swept back into power in late 2015 after nearly a decade, playing on fears sparked by the refugee influx.

Its leader Jaroslaw Kaczynski has said refugees bring "cholera to the Greek islands, dysentery to Vienna, various types of parasites".

- NORWAY: The Progress Party joined a government coalition in 2013 after winning 16 percent of the vote. The party's Sylvi Listhaug, immigration and integration minister, has said "the tyranny of kindness is blowing over Norwegian society like a nightmare".

- DENMARK: The Danish People's Party won 21 percent of the vote in a 2015 legislative poll. The minority government needs the party's support to pass legislation.

Denmark introduced a host of measures to deter migrants earlier this year, including allowing police to confiscate some of their valuables to help pay for their accommodation.

- FINLAND: The nationalist Finns Party won 18 percent of the vote in 2015 legislative elections and is now a part of the government coalition, although its popularity has fallen. Party leader Timo Soini is foreign minister.

- Brexit ripple effect -

- BRITAIN: A historic vote on June 23 to leave the EU was the biggest success to date of populist movements since the bloc was founded.

The "Leave" victory was driven in large part by worries about immigration, economic uncertainty and a perception that an out-of-touch Brussels elite was making the rules.

With the Labour Party in crisis, the new head of the eurosceptic UK Independence Party (UKIP), Diane James, has said she wants the group to become Britain's main opposition force.

- FRANCE: The National Front (FN) has notched up several local electoral successes since 2012. The FN's Marine Le Pen has likened the migrant influx to the "barbarian invasions" of the fourth century.

Boosted by the succession of Islamist "terror" attacks in France, polls consistently tip Le Pen to reach the second round of France's presidential election in 2017.

- NETHERLANDS: The far-right Freedom Party is currently leading polls for a March 2017 legislative vote. The party's platform calls for a closure of "all mosques and Islamic schools" and "a ban on the Koran."