Two preliminary rulings today from the European Court of Justice have supported trade unions opposition against the use of imported lower paid labour from the newest members of the European Union in Eastern Europe.

In one judgment the European Court of Justice said that trade unions should be allowed to compel companies from other member states to comply with local wage agreements.

Today's opinions by two Advocates General of the Court are important as countries such as France and trade unions in the rich countries such as Ireland, object to what is termed social dumping.

One case before the Court involves a group of Latvian workers who were given a project to renovate a school in Sweden at half the rate of pay of their Swedish counterparts.

The ruling today found that the Swedish trade union at the centre of the dispute was entitled to insist that the Latvian company providing the workers, sign up to the same wage agreement which governed Swedish construction workers.

The Advocate General argued, however, that this right had to be proportionate and in the public interest.

In a separate case, the Court found that unions could take action to prevent a ferry company from relocating to another member state in order to employ staff at lower rates of pay.

The case related to a Finnish ferry company which reflagged one of its vessels in Estonia.

However, unions were not entitled to prevent the relocation of a company if it was simply to protect jobs in their own country.

This would have the effect of partitioning Europe's labour market along national lines and was contrary to the principles of non-discrimination in community law, the court ruled.

This case was similar to the Irish Ferries dispute with SIPTU in 2005 over the employment of Latvian workers on a number of vessels.

The two opinions/rulings are not binding on the Court, which will issue a full judgment in several months time. However, in 80% of cases, the Advocate General's opinion is confirmed later.