Of the 2,560,000 people registered as employed by the tax authorities last year, 387,103 were foreign nationals, newspaper Bergens Tidende reports.

Kjell Gunnar Salvanes, a professor of economics at the NHH business school, said Norway’s economy had benefitted hugely from an influx of foreign workers since the last major EU enlargement eight years ago.

“Since 2004, immigration has switched from low-qualified asylum seekers to well-qualified workers from Eastern Europe and Sweden. And that change has come about very quickly,” he said.

The 2004 EU enlargement gave increased access to the Norwegian labour market to citizens of Poland, Estonia, Latvia, Lithuania, Slovakia, Slovenia, the Czech Republic, Hungary, Cyprus and Malta.

Since then, workers have poured in to take up jobs on a strong Norwegian labour market. For example, the period has seen a seven-fold increase in the number of Polish tax payers, with some 70,000 Poles now working in Norway.

Salvanes said Norway had experienced a form of mass immigration over the last eight years that was comparable to the vast wave of emigration to the United States more than a century ago.