The European Union appealed to member countries on Tuesday to deliver on promises to deal with the refugee emergency, warning that the EU's credibility is at stake.

More than 600,000 people have entered Europe by land and sea this year seeking sanctuary or jobs, overwhelming border authorities and reception facilities. More than 3,000 have died.

In response, EU leaders promised to share refugees from Italy and Greece, boost spending and send police, border guards and experts to help register the arrivals.

But so far actions have not matched the speeches delivered at five migration-focused summits this year.

"The gap between the pledges and what is on the table must be reduced, otherwise we are losing all kinds of credibility," European Commission President Jean-Claude Juncker told EU lawmakers.

The EU's executive arm has drawn up plans to move 160,000 refugees from Italy and Greece over the next two years to ease their burden.

"Nine member states have let us know that they can soon relocate 700 people," Juncker said. "But let's not forget that we have a decision to relocate 160,000 refugees in need of international protection."

The EU's border agency Frontex has appealed for 775 experts to help register, screen and fingerprint people, but so far almost half that number has been pledged.

"Half is not enough, we need more," said Juncker, warning that funding and experts are "crucially essential if we want operational decisions to be implemented."

The Commission has now earmarked almost 10 billion euros ($11 billion) for spending on migration policy this year and next, he noted.

A month ago, EU nations promised to provide an extra 2.3 billion euros, but so far only 86 million euros has been pledged.

Juncker said countries are "moving slowly at a time when they should be running."