The European Commission is to carry out an investigation into complaints made by the IMO about excessively long working hours of Irish junior doctors.

The IMO says the Commission will now examine Irish breaches of the EU working time directive (EWTD), which stipulates that junior doctors' working weeks should not exceed an average of 48 hours.

Currently, Irish NCHDs (junior doctors) are working on average 63 hours per week and some are working for up to 100 hours.

The Commission has told the IMO it will "assess the progress made by the national authorities in improving compliance with the directive with a particular emphasis on the period January - June 2013."

The IMO recently launched a campaign to highlight long doctor working hours.

It says it is balloting of NCHD members on next month to seek approval for industrial action - up to and including strike action - on this issue.

Val Moran, Senior Industrial Relations Executive with the IMO, said that Government's failure to implement the EWTD for NCHDs was exposing the Irish taxpayer to the risk of millions of euros in fines.

"Each time the EWTD is flouted the Commission can fine the Irish Government.  As the EWTD is being flouted in hundreds of cases every day of the week, the potential exposure of the Irish Government is enormous."

15% of junior docs are agency staff