The EU Working Time Directive which limits the working hours of junior doctors comes into effect in the State tomorrow.
It is estimated that between one in five and one in six doctors will be compliant with the directive, despite the absence of agreement on its implementation between the Irish Medical Organisation (IMO) and the Health Service Employers' Agency (HSEA).
This is because some doctors already work shift patterns.
Talks on the implementation of the EU directive have been adjourned until mid-August by the Labour Relations Commission.
The IMO and the HSEA held a five-hour meeting in Dublin on Tuesday without making progress. The talks stalled over an inability to agree new rosters for non-consultant hospital doctors.
Under the directive, non-consultant hospital doctors should not work in excess of 58 hours a week, averaged over one year. They must be given 11 consecutive hours of rest within each 24- hour period and 35 consecutive hours of rest every seven days.
However, under one interpretation of the directive, outlined by the Department of Health, doctors could be asked to work up to 91 hours a week.
According to guidance issued to health service employers it would be possible to roster a doctor for up to 11½ days in succession while still complying with the legislation.
Employers face significant fines for every day the European Working Time Directive is breached. Under the legislation junior doctors are entitled to seek compensation via an employment rights commissioner. Compensation can be up to two years' remuneration.
Both the IMO and the HSEA have indicated that industrial action on the issue of the directive was unlikely while both sides were engaged in a formal process with the Labour Relations Commission.
Employers claim that junior doctors are seeking to protect overtime earnings while maintaining a working day of 9 a.m. to 5 p.m. However, the IMO argues that the issue is not about pay but about safe rostering and ensuring junior doctors receive appropriate training under the supervision of consultants.