The European Union's border agency on Monday urged member states to provide hundreds more personnel as it struggles to cope with a record migrant crisis.

Frontex said it needs 775 more guards to "be deployed at the external borders of the European Union" after it revealed 630,000 people entered the bloc illegally so far this year.

"This is the largest number of border guards Frontex has ever requested in the history of the agency," it said in a statement.

"Above all, new border guards must reinforce teams in Greece and Sicily in charge of registering new arrivals, but some of them must be deployed on the EU's land border," Frontex spokeswoman Ewa Moncure told AFP.

Europe is relying on huge new so-called hotspot camps in Greece and Italy to hold migrants while their claims for asylum are processed.

"If we had one or two thousand European border guards to help the Greek authorities, it would have a spectacular effect on the crisis there," Frontex executive director Fabrice Leggeri told French media on Sunday.

"Member states must understand that in place of deploying hundreds of police at their national borders, it would be more useful to send them to the (EU's) external border," he said.

His appeal comes as the EU is gearing up for an October 15-16 summit specifically aimed at hammering out policies designed to meet the challenges posed by the migrant crisis.