MONTREAL - The fight to abolish 24-hour shifts for medical residents isn't over yet.

The McGill University Health Centre is contesting a ruling that would limit residents to 16 consecutive hours.

An arbitrator ruled in favour of Quebec's federation of medical students in June and gave the MUHC six months to comply with the ruling.

But the health centre argues that's not enough time to implement a new shift system and is asking for the deadline to implement the changes to be extended until July 1, 2012.

In its application filed in Montreal court, the health centre also contested the argument that 24-hour shifts can be dangerous.

Dr. Charles Dussault, president of the Quebec Medical Residents Federation, told The Canadian Press he was disappointed with the application for judicial review.

"For us it is a safety issue," he said.

In June, an arbitrator ruled that 24-hour shifts violate the Charter of Rights and Freedoms and gave Quebec hospitals six months to change work schedules for medical residents.

The fight over shift length began four years ago when a medical student filed a grievance against McGill University saying that working for 24 hours in a row put his health at risk and threatened patient care.

Three Montreal hospitals have decided to limit shift length themselves.

Last year, the Jewish General Hospital, the Royal Victoria Hospital and Montreal General Hospital decided residents studying internal medicine would work day shifts or overnight shifts, but not both.

Many medical professionals say doctors-in-training get the chance to learn and practice much more on the overnight shifts.

with files from The Canadian Press