A German doctor from Kiel had turned to his local court arguing that the time he spent "on-call" should be considered as full working time even if he is allocated a room with a bed in the hospital where he may rest when his services are not required.
German law differentiates between full working time (readiness for work) and rest time (on-call service and stand-by).
The Labour Court of Schleswig-Holstein referred the case to the European Court to determine whether the German law is conform to Community rules.
The European Court of Justice ruled on 9 September that since the doctor performing on-call duty is "required to be present at a place determinded by the employer and to be available to the employer in order to be able to provide their services immediately in case of need", the German law defining such duty as a "rest period" is in conflict with Community directive 93/104 on working time.
According to a Commission spokesperson, the German government estimates that the ruling could cost up to two billion euros and necessitate the employment of an additional 20.000 doctors and nurses.
The Commission said it would publish a report on the impact of the working time directive by the end of the year.