Health chiefs still do not know the cause of an outbreak of a potentially dangerous bacteria which has delayed the opening of Belfast's new maternity hospital by years, MLAs have been told.
Stormont's Health Committee heard that lessons have been learned to avoid similar problems with the construction of a new children's hospital in the city.
But one MLA said she was "underwhelmed" by the performance of the Belfast Trust in managing major projects, while another compared it with a "farce from The Thick Of It" comedy TV programme.
It was disclosed last year that the opening of Belfast's new maternity hospital would be significantly delayed, after high levels of the bacteria pseudomonas were discovered in its water system.
The hospital, which was already several years late and over budget, had been expected to open this year and the Belfast Trust took possession of the new building last March.
Earlier this year it was announced that construction work would begin on Belfast's new £671 million children's hospital, which will be sited beside the maternity building on the Royal Victoria Hospital site.
Philip McClay, director of health estates at the Department of Health and David Porter, director of strategic development at Belfast Health and Social Care Trust, updated the committee on the governance arrangements for the build of the hospital and lessons learned from the build of the maternity hospital.
MLAs were told that the children's hospital would have separate water systems on each floor, unlike the single water system in the maternity hospital.
Alliance Party MLA Danny Donnelly asked for an updated timeline on the opening of the maternity hospital.
Mr Porter said there would be multi-disciplinary review meeting at the trust next week and he was unable to give an updated timeline.
DUP MLA Diane Dodds asked why the interim chief executive of the Belfast Trust, Maureen Edwards, was not answering questions in front of the committee about lessons learned from the maternity hospital build.
She added: "I am underwhelmed by all of this. I have called for an independent voice looking at what has happened in the Belfast Trust.
"We have the critical care building, we have the acute mental health building which seems to be an absolute shambles, we have a maternity hospital costing almost £100 million, and a year after it was announced it was finished, we still can't use it.
"I am looking forward to a children's hospital that is built without problems and on budget. But I do think we need to have a critical look at what has happened in the Belfast Trust."
SDLP MLA Colin McGrath said: "It just seems to have been run like a farce from The Thick Of It, where things just go over budget and take longer than they need to."
He asked if it had been established what had caused the pseudomonas issue in the maternity hospital and what was being done to mitigate against it in the children's hospital build.
Mr Porter said: "I don't think we can sit here and say we have identified a singular source, in all honesty. But what we do know are that there are lessons learned as to what may have been contributory factors."
He said a number of steps were being looked at, including avoiding risks by keeping the water system dry for as long as possible before it was operational.
He added: "All I can say is we haven't been able to identify a single point of cause on the maternity. We are certainly working with every aspect of the design and the systems in place to make sure we mitigate that risk moving forward."
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