Ireland is among seven countries facing European Court action for failing to introduce laws recognising the qualifications of a range of workers.
These include "itinerant tradesmen".
The EU rules are designed to make it easier for people to move around EU countries and set up shop if they wish without being blocked by red tape.
Many professional qualifications, such as those of doctors, lawyers, teachers, are already given equal recognition in all 15 member states.
But Ireland and the rest were given until the end of July last year to extend the law to cover "industrial, commercial and craft occupations".
That means workers such as electricians, tilers, hairdressers and itinerant tradesmen, according to the Commission today.
Governments were meant to transpose a Directive on the recognition of their qualifications into domestic law.
Now Ireland, Britain, Germany, Spain, Italy, the Netherlands and Austria have been notified that the Commission is bringing a court action against them.
It is on the grounds that failing to apply the EU Directive "is likely to prove an obstacle to the free movement of workers, freedom of establishment and freedom to provide services in the sectors concerned".