The European Commission has decided to move ahead with proposed new rules on cross-border workers, despite opposition from Central and Eastern European countries that say it would hurt their workers unfairly.

The move will likely further worsen the already strained relationship between Brussels and the EU’s eastern members, who argue the rules will make it more difficult for their workers and companies to find employment and contracts in Western Europe

In March the commission proposed revising the existing rules in a bid to smooth wage differences between local workers and those sent abroad in the bloc. The proposals will mean that companies in the eastern part of the bloc that send their workers temporarily to a western European country, must pay them the same wage locals earn.

Governments in richer countries like France and Germany are backing the proposals as they try to cope with a populist anti-immigration backlash among their voters. Workers in these countries fear they are losing out on jobs because of unfair wage competition.

Although posted workers make up only 1% of the EU’s workforce, their number has jumped 44% over the past decade. There are currently 1.9mn posted workers in the EU, half of them are sent to France, Germany and Belgium.

A group of 11 predominantly eastern member states, including the Visegrad and Baltic countries, are opposing the reform saying it goes against the principles of free movement and competition in the bloc. The 11 countries tried to block the reform by using the “yellow card” mechanism, which allows national parliaments to call on the European Commission to reconsider its position.

The commission, however, rejected the “yellow card” procedure and decided to go ahead with the changes, saying they do not violate the subsidiarity principle. “All things considered, we have concluded that our proposal fully complies with the principle of subsidiarity and we will therefore maintain it. Posting of workers is a cross-border issue by nature. The Juncker Commission remains firmly committed to the free movement of people on the basis of rules that are clear, fair for everybody and enforced on the ground," EU commissioner for employment Marianne Thyssen said in a statement.

“If the commission cannot understand the dissent expressed by 11 EU countries in the case of posted workers, that means they haven’t learned anything from Brexit,” the Polish EU affairs minister Konrad Szymanski said, according to Politico.

The Czech State Secretary for EU affairs, Tomas Prouza, agrees: “After the Brexit vote, the promise was to work on topics that are unifying, not divisive. Having such a divisive decision is not in anybody’s interest at the moment,” the Financial Times cited him as saying.

“We do not divide, we try to bridge. The problem was already there before we came up with this proposal, Thyssen responded when asked about a divide between eastern and western member countries on the proposal, Politico reports.