Brussels - From Italy's ruling League to Marine Le Pen's National Alliance in France and the Fidesz party of Hungarian Prime Minister Viktor Orban, populist parties are making waves in Brussels by vowing to rebuild the European Union in their image.

European "earthquake"

Steve Bannon, the former strategist of US President Donald Trump, has predicted that European Parliament elections in late May will deliver "an earthquake" in which eurosceptic parties take control.

Many fear that the EU legislature - which has been dominated for most of its 40-year history by a grand coalition of the centre-left and centre-right - could be paralysed by such a surge on the political fringes.

The new parliament will be instrumental in appointing the next members of the EU's executive, the European Commission, before taking up its regular work of vetting any new initiatives and voting on key issues such as the bloc's future budget.

"For many people, Europe represents a nightmare and not a dream," Italian Deputy Prime Minister Salvini said at a recent event during which he invited other populist parties to join forces with his far-right League.

"We are working for a new European dream," Salvini added. "The objective is to be the first, the most important, the most numerous group [in parliament]."

Austria's ruling Freedom Party, France's National Rally, the Alternative for Germany (AfD), the Danish People's Party and the Finns Party are among those who have joined forces with the League's platform.

National Rally leader Le Pen predicted in February that parliament will be "turned upside down" by the rise in pro-sovereignty parties that argue for individual European states to have more power, and Brussels to have less.

Far-right and far-left groups

An April 18 survey conducted on behalf of the parliament shows the three main far-right groups - the European Conservatives and Reformists; Europe of Nations and Freedom; and Europe of Freedom and Direct Democracy - with 23 per cent of the vote, not much above their current 20-per-cent share.

However, this puts them just seven seats short of the 180 projected for the leading centre-right European People's Party - out of an overall 751 seats - and significantly ahead of the centre-left Socialists and Democrats.

Part of the increase can be attributed to an expected short-lived boost for British eurosceptic parties, after London was granted a Brexit delay until late October.

Taken together with a predicted rise of far-left groups, such as the movement of French radical leader Jean-Luc Melenchon, eurosceptic parties could well win around a third of all seats in parliament, according to the European Council on Foreign Relations (ECFR).

The risk is genuine - if the left and the right manage to cooperate, says Susi Dennison of ECFR.

"It's important to keep in mind that they are quite a diverse group," Dennison tells dpa.

Migration issue

Even on the issue of migration, Italy's League - which wants the EU to take more refugees off Rome's hands - is at odds with Hungary's anti-migrant Fidesz party, she notes.

The rise in populism has been associated largely with a record influx of refugees and migrants to Europe in 2015-16.

The May polls will "determine the future of European civilization," Hungary's Orban, a key proponent of the anti-migration agenda, said this month.

He predicted that traditional political divisions between left and right will give way to a split between those promoting migration and those rejecting it.

Contrary to the headlines, however, the 2019 EU elections "will not be a referendum on migration," according to the ECFR.

Migration is not a defining issue for most voters, the think tank argues, citing data collected with the YouGov polling institute in 14 of the EU's 28 countries.

More concerns, fears and threats

According to the survey, the greatest threat for most Europeans is Islamic extremism - which is not to be confused with the migration issue, as it is more likely to mobilize centre-right voters than those on the fringes, the ECFR argues.

Contrary to populist narrative, many in fact fear that "nationalism will destroy the EU," according to the think tank, while the economy, climate change and the threat of Russia also top migration in certain countries.

Meanwhile, another figure will be closely watched from Brussels: the turnout. Participation in EU elections is traditionally low; according to the poll by ECFR and YouGov, just 43 per cent of those asked said they would definitely participate in May.

"It's a big issue because it deals with the legitimacy of the European Parliament," says Nathalie Brack, a visiting professor at the College of Europe.

A turnout of less than 40 per cent would send a "major signal" that efforts to increase interest in the elections have failed, she says. Surprisingly, eurosceptic parties may play an important role here.

"Without the eurosceptics, I think the turnout would be much lower in some countries," Brack says, adding: "They mobilize people and they force the other parties also to talk about Europe in the elections, instead of national issues."

"That's one of the credits that eurosceptics and populists deserve," Brack notes.