Manfred Weber, the European People's Party President, has urged the EU to get a handle on migration in order to avoid a far right surge.
He warned: "If we do not find the solution or proper common understanding how to manage migration, then I’m very worried about the next European elections".
Weber described the surge in popularity of the far-right Alternative for Germany (AfD) as a "great shock and a matter of concern", also pointing to far-right Geert Wilders' win in the Netherlands last week.
Speaking to Politico, he added: "People must see that we are not only talking about migration … but really find a solution … to stop illegal arrivals on European soil."
WATCH: Von der Leyen says 'we will decide who comes to the EU'
Countries including France, Slovakia, Sweden and Germany have re-instated border restrictions including identity vetting, passport checks, police interviews, static checkpoints and vehicle inspections.
Such restrictions on movement were abandoned many years ago as part of the Schengen Treaty.
But they are now viewed by a number of countries as being essential to stop "infiltration" by terrorists posing as migrants.
Peter Szijjarto, the foreign minister of Hungary, issued a warning to the EU over its migration policy earlier this month.
He said: "If Brussels does not change its migration policy, we could find ourselves where we do not want to be: in an era of Europe torn apart by old borders."
This came after Italy escalated its own internal border checks with neighbouring Slovenia as part of an attempt to reduce the "increased threat of violence within the EU", which the country believes has escalated since the outbreak of the Israel-Hamas war.
Germany's crackdown on migration came amid a surge of the far-right AfD.
The party made gains in two state elections in October, coming second in Hesse and third in Bavaria.
The results both represent historic gains for the party.