Brussels "has indeed confirmed its decision to take action before the court," Hansen said. "Now it's for the court" to decide.

EU nations put themselves on collision course with the bloc's executive after deciding to slash in half a 3.7 percent salary increase drawn up under a formula previously agreed by national leaders.

The salary dispute has proved an embarrassment at a time when European leaders are trying to re-brand the bloc on the world stage with new leadership figures under its reforming Lisbon Treaty.

The legal battle could even become complicated by the fact that judges set to hear the case themselves would benefit from the higher pay raise.

Some 50,000 EU employees and contract staff -- at the European Commission, parliament, council and court -- will only receive a 1.85 percent rise, despite having taken strike and other industrial action backed by unions.

Some member states have cut civil servants' salaries domestically in a bid to reduce swelling national deficits, sometimes under orders from Brussels, where the commission also acts as a budget watchdog.

The commission argues that its original figure of a 3.7 percent pay rise was calculated through a legally-binding mechanism, averaging pay rises in Brussels and eight EU countries.

A 1973 court judgment in a near-identical case backed the commission's stance.

Twenty EU nations supported a decision last month to invoke an unusual written procedure to cut the raise. Seven others abstained but all face the same court complaint, which targets the collective entity for the 27, the European Council.

The commission said it had asked for a speedy decision by the European court for a case which could otherwise trundle on for over a year.

The row could nonetheless disrupt EU parliament confirmation hearings beginning on Monday for Barroso's new team.

The two key figures there are the EU's new foreign affairs supremo, Britain's Catherine Ashton, and top financial services overlord, France's Michel Barnier, both of whom face grillings from opponents in the European Parliament.

Basic gross monthly salaries for EU commission staff range from 2,550 euros (3,800 dollars) for a secretary to around 17,700 euros for a department head.

The 27 commissioners themselves get even more, plus housing and other perks.

The new European Union president, Herman Van Rompuy of Belgium, is to earn more than US President Barack Obama.