Major concerns have been raised over the ongoing delay in a final decision over the future of paediatric cardiac procedures in Belfast.
It has been more than a year since restrictions on the number of children receiving surgery in Northern Ireland were introduced.
Heart operations are still taking place in the Royal Victoria Hospital.
However, children with complex diagnoses have been transferred mainly to Birmingham Children's Hospital in England.
Calls have now been made for Health Minister Edwin Poots to provide clarity on the matter.
Robin Swann MLA said, to date, Mr Poots had failed in his basic duty to do so.
"The Health Minister needs to come forward and say why the restrictions were placed on cardiac services here, on what grounds the decision was taken, and finally, for how long is it going to last," he said.
"Last year alone the number of paediatric cardiac procedures carried out on children in Belfast was 58, compared to 74 having to travel outside of the province."
Children's Heartbeat Trust has campaigned for the retention of children's heart surgery in Northern Ireland. Last year a national report said such centres across the UK must perform a minimum of 400 children's surgical procedures each year.
Belfast currently falls short of that number.
A working group recommends an all-island service. Children who require surgery will be expected to travel to Our Lady's Children's Hospital in Crumlin, Dublin.
A spokeswoman for the Department of Health said: "The length of time that these restrictions will remain in place is a matter for the Belfast Health and Social Care Trust.
"As the minister has already indicated, there has been no independent assessment of the decision taken by the Belfast Health and Social Care Trust to introduce a more rigorous case selection.
"He hopes to make his final decision on the future arrangements for the service as soon as possible."
Last year a review of children's congenital heart services in Northern Ireland found it is no longer sustainable. About 90 heart surgery operations are carried out each year by the Belfast Health Trust.
Health Minister Edwin Poots said all options should be considered, including an all-Ireland service. If that is not suitable, children will have to travel to England if facilities here are scrapped.
The surgical service for congenital heart disease in Belfast is currently provided by two surgeons, with support where needed from two further surgeons based at Our Lady's Hospital for Sick Children in Dublin.