The future of children's cardiac surgery at Belfast's Royal Victoria Hospital is in serious doubt.
The North's Health Minister Edwin Poots said a team of international experts recommended the service should move to Dublin.
Hundreds of families have campaigned for it to be retained in Belfast.
Publication of the review is long overdue, but it is understood the delay is due to surgeons in Dublin stalling on how they might facilitate an all-Ireland service.
Such a service would be shared by Our Lady's Children's Hospital in Crumlin, Dublin, and Belfast's Royal Victoria Hospital.
One of the options the team explored was the viability of a cross-border service, with some element of surgery being maintained on the RVH site.
However, this would require Dublin surgeons agreeing to travel north to perform surgery in Belfast.