The head of a liberal group in Europe warned that the European Union may become ungovernable if the far-right obtains a significant amount of the votes in the upcoming European Parliament election in June as they recently did in the Netherlands.

Far-right parties, including Marine Le Pen's National Rally in France and Matteo Salvini's League in Italy, are expected to prosper in the June election with pledges to toughen the bloc's approach to immigration and soften climate policies.

"With the rise of populists almost everywhere in Europe of the extreme right, we risk having an ungovernable Europe," Stéphane Séjourné, leader of the centrist Renew Europe group, said on Tuesday.

Renew, the center-right European People's Party and the center-left Socialists and Democrats group formed a coalition five years ago to agree on broad policy outlines and divide up top EU jobs.

The three have 420 of the 705 seats in parliament.

However, anti-immigration populist Geert Wilders' win in the Dutch election has sent a warning to mainstream politicians. In France, President Emmanuel Macron's party, which makes up a quarter of Renew, trails far-right leader Marine Le Pen's by 8-10 percentage points.

"The risk is that it could prove very difficult to form a majority," Séjourné told a group of journalists.

The French lawmaker ruled out any alliance with the far-right or with the eurosceptic European Conservatives and Reformists group. It includes Poland's Law and Justice party that battled Brussels for eight years. He also expressed skepticism toward the Greens group.

Séjourné said mainstream parties should point to an EU agreement reached on hosting migrants and focus attention on other topics, such as the green and digital transitions and defense.