Senior figures in the trade union movement believe that while the advocate general's opinions set out yesterday would not confer additional rights on workers they would, if upheld by the court, re-iterate their traditional understanding that members had a fundamental right to undertake collective action.
The advocate general opinion in the Laval case in Sweden would appear to suggest that there is nothing in EU law to prevent unions taking collective action to force any company seeking to bring in workers from another member state to pay the local rate for the job.
It says that where a member state has no system for declaring collective agreements to be of universal application, the relevant EU directive "must be interpreted as not preventing trade unions from attempting, by means of collective action in the form of a blockade and solidarity action, to compel a service provider of another member state to subscribe to the rate of pay determined in accordance with a collective agreement which is applicable in practice to domestic undertakings in the same sector that are in a similar situation and was concluded in the first member state, to whose territory workers of the other member state are temporarily posted".
The opinion, however, says that the action would have to be proportionate and be motivated by "public-interest objectives".
Siptu president Jack O'Connor suggested that the term "blockade" could be interpreted as a boycott of the company concerned.
However, he said that the opinion would also indicate that any action would have to be genuinely aimed at protecting workers and not an indirect attempt to prevent the freedom of movement.
Mr O'Connor welcomed the opinion and said that they represented "major steps forward in the fight against those employers who fundamentally oppose the rights of workers to defend collective agreements from being undermined through the use of sweated labour".
The Irish Congress of Trade Unions (Ictu) said it particularly welcomed "the confirmation that private companies do not enjoy greater rights than workers".
Ibec director Brendan McGinty said flexibility in the labour market was hugely important and it would be concerned at any new measures that would interfere with capacity of employers to put in place terms and conditions.