The EU parliament on Wednesday adopted a contentious reform of Europe's asylum policies that will harden border procedures and force all the bloc's 27 nations to share responsibility.

The parliament's main political groups overcame opposition from far-right and far-left parties to pass the new migration and asylum pact -- a sweeping reform nearly a decade in the making.

German Chancellor Olaf Scholz called the new rules a "historic, indispensable step" for the European Union.

EU home affairs commissioner Ylva Johansson said the bloc "will be able to better protect our external borders, the vulnerable and refugees, swiftly return those not eligible to stay" and introduce "mandatory solidarity" between member states.

Ten pieces of legislation in the overhaul were passed.

Outside the Brussels parliament building, dozens of demonstrators protested against the vote, echoing criticism from more than 160 migrant charities and non-governmental organisations who view it as a betrayal of European Union values.

In a sign of the fierce opposition, the start of voting was interrupted by protesters in the public gallery yelling "This pact kills - vote no!" until the chamber was brought to order.

But the UNHCR refugee agency's chief has endorsed the reform, drawn up by the European Commission since massive inflows jolted the bloc in 2015.

For the far-left, the reforms -- which include building border centres to hold asylum-seekers and sending some to outside "safe" countries -- were incompatible with Europe's commitment to upholding human rights.

It was "a pact with the devil," said Damien Careme, a lawmaker from the Greens group.

Far-right lawmakers complained the overhaul did not go far enough to block access to irregular migrants, whom they accuse of spreading insecurity and threatening to "submerge" European identity.

"We won't allow ourselves to be replaced or submerged," Jordan Bardella, a lawmaker heading France's far-right National Rally party whose figurehead is Marine Le Pen, said in the pre-vote debate.

The mainstream centrist right and left in parliament had called for the pact to be passed as an improvement over the current situation.

They warned that failure to pass the reforms would boost the far-right, predicted to become a bigger force in the European Parliament following June elections. (AFP)