The floor, which has been earmarked for cardiology services, has never been occupied, despite a year-long waiting list for children with heart problems.

A spokesman for the HSE said all the funding for developments in the Medical Tower had already been handed over to the hospital, and that the HSE had no further responsibility for the matter.

However, when the Sunday Tribune contacted a spokeswoman for Crumlin hospital, she could not provide any explanation for the floor remaining vacant for three years.

"I think it just speaks volumes about the attitude towards cardiology services for children, " said Shay McConnell, director of Heart Children Ireland. "I was there three years ago when Mary Harney opened the building and yet we're still waiting for the services."

McConnell said Heart Children Ireland had been in regular contact with the hospital in an effort to find out when the floor is due to be open.

"Every time we ask, we're told it's 'in progress', " he said. "The last completion date we were given was June, and now we've been told that it won't be ready until the end of the year. Realistically, I'd say we're looking at 2008 before it's up and running. And all of this while there's a year-long waiting list for children to see a cardiologist. It says a lot about the attitude towards child cardiology treatment in this country."

A statement from Our Lady's Children's Hospital said the works on the cardiac outpatients department were due to be completed on Friday last, when the builder was to hand over the floor officially to the hospital. It said the tender process for equipment for the unit had already begun.

"Over the next couple of weeks, an infection control screening process will begin, " said the statement. "The cardiac OPD will be fully kitted out and due to be open in September 2007. The Heart Children's Group have been notified of these upgrades and are happy that no cardiac surgery has to be cancelled."

The spokeswoman did not answer the Sunday Tribune's query as to what the original deadline was for the opening of the cardiac unit.

Just a few weeks ago, the hospital confirmed that the waiting time for routine cardiac outpatient referrals is now more than 12 months. That news came just one day after it emerged that the HSE had warned the hospital that it faced a deficit of 16m at the end of the year unless it controlled costs and cut staff back to approved levels.