The figures were revealed after John O’Dowd questioned the Northern Ireland Health Bodies.
John O’Dowd said he knew of a family who had been waiting 16 years to get compensation for their son, who became severely disabled after some medical treatment he had under-took went wrong.
When speaking with the BBC Mr O’Dowd said that legal fees over 27 years could run into millions.
He said: “The case is continually cancelled just before it reaches court, leaving the family in limbo.”
In the written reply it reveals that the Health and Social Care Board has over 55 cases that have been on-going for over 15 years.
A spokesperson for the department of health, Social Services and Public Safety told the BBC: “Every effort is made by hospital staff to ensure that the highest standards of care are provided to all patients.
“Inevitably, there will be a small number of occasions, particularly in emergencies involving critically ill patients with complex needs where problems occur.”