Brussels - EU negotiators agreed Thursday on the establishment of a European Labour Authority aimed at supporting the estimated 17 million Europeans living or working in another member state and cracking down on black market labour.

European Commission President Jean-Claude Juncker, who had proposed the idea in 2017, welcomed the decision as a "big step forward" for the European Union.

The aim of the agency will be to help inform employees, firms and national bodies of their rights and obligations in cross-border situations; ease cross-border inspections; mediate in disputes; and help tackle undeclared work, among other things.

It will provide "crucial assistance" to national administrations, said Romanian Labour Minister Marius-Constantin Budai, whose country holds the EU's rotating presidency.

However, member states will only take part "on a voluntary basis," he noted.

The European Labour Authority is due to be up and running before the end of the year, according to the deal reached by representatives of the European Parliament and member states.

It will employ around 140 people and have an estimated annual budget of roughly 50 million euros (56.4 million dollars), according to the commission. The seat of the agency has not yet been decided.

The agreement still requires official approval by the EU legislature and capitals, a move that is expected to be a formality.