The European Union must drop barriers to immigration to boost growth, according to the Organisation of Economic Cooperation and Development, in clear opposition to arguments put forward by the leave camp in the EU referendum that the UK would prosper despite restrictions on migrant workers.

The Paris-based thinktank, which is funded by the world’s richest nations, said the EU needed to encourage workers to move to where they can find a job by forcing countries to recognise professional qualifications and allow workers to transfer their pensions.

In its latest survey of the EU and the eurozone, the OECD said obstacles to labour mobility remained one of the three significant barriers to growth, alongside a failure to break the banking sector’s monopoly on lending to businesses and Brussels’ inability to tackle restrictions that remain in the single market.

“Barriers to intra-EU labour mobility, including recognition of professional qualifications and supplementary pension portability, remain significant and need to be reduced. Labour market requirements for non-EU migrants should be further standardised,” the OECD said.

It also said the inflow of refugees was “a major and pressing challenge” that must be met collectively by the EU countries.

“A coordinated and comprehensive response is crucial to ensure effective provision of international protection, sharing of costs and successful integration of refugees,” it said.

The reports follow a series of stinging criticisms of the EU by the OECD, which has argued that austerity has been clumsily applied while governments rely too heavily on monetary easing by the European Central Bank.

The report said: “Europe has made important progress in harnessing and reinforcing its policies and institutions to recover from a double-dip recession and improve crisis management.

“Very supportive monetary policy has helped growth to pick up gradually over the past two years, and contributed to reduce tensions in sovereign debt markets. The effect of fiscal policy on demand has turned broadly neutral. Confidence in the European project has recovered from its lows in 2013, although it is still well below what it was before the crisis.

“However, many legacies of the crisis are still unresolved, and major new problems have emerged.”