Health Minister Mike Nesbitt has said he has been made aware of a further “totally shocking” problem with Belfast’s new maternity hospital.

Mr Nesbitt faced calls to share the information with MLAs during a debate calling for an independent inquiry into the maternity and children’s hospital project, which has been beset by delays.

It followed the revelation from a DUP MLA that a potentially dangerous bacteria was found in 459 water outlets in the maternity hospital.

The figure was revealed by Diane Dodds as she launched a motion into the delay in opening the site.

It was revealed earlier this year that the maternity hospital opening was facing a new delay after high levels of the bacteria pseudomonas were found in water systems.

The hospital had been expected to open next year when the Belfast Trust took possession of the new building in March.

However, during testing of its water systems, high levels of Pseudomonas aeruginosa (PsA) were discovered, leading the trust to say the project was facing a significant new delay.

Pseudomonas aeruginosa is found widely in soil and stagnant water.

It does not usually cause illness in healthy people but can pose a serious threat to people with weak immune systems.

Responding to the motion calling for an independent inquiry, Mr Nesbitt said: “When I went to bed last night I was not in favour of that, not least because the cost and time associated with a further independent inquiry could be in the order of £3 million per annum with a significant time impact and no guarantee of improvement and it could potentially stymie progress.

“However, as of eight o’clock this morning I have become aware of another issue.

“I know Mrs Dodds is very well informed on these issues so I challenge her, I give her 24 hours to discover what the latest problem is with the maternity hospital.

“It is another shocking, another totally shocking revelation.”

Raising a point of order, Mrs Dodds said: “If he indicates that there is another problem, in the context of this debate he should share that information with the House.”

She had earlier told the debate that increases in costs for the new maternity and children’s hospitals were “astronomical” and were putting “intolerable pressure” on the health budget.

DUP MLA Diane Dodds (Brian Lawless/PA)

Referring to the maternity hospital, she said: “Shortly after the (Belfast) trust took charge of the building, pseudomonas was confirmed in a significant number of water outlets, rendering the hospital unsafe and requiring significant reparative work.

“Indeed an answer to a written question I received just today indicates that this is in fact 459 different water outlets and that is 36% of the total water outlets in the building.”

Mrs Dodds said she had received further information from Mr Nesbitt that the trust’s water safety team was not involved in the handover of the building from the contractor in March.

She said: “A full independent inquiry should take place, outwith the Belfast Trust and those who participated or acted in a professional advisory capacity in the decision making.”

The MLA said she also wanted to know the extent of the risk assessment carried out by the trust before the handover of the building.

She said: “Northern Ireland cannot afford losses on this scale.

“I do think that those who made these decisions around the handover of the contract and the decision to proceed need to be held accountable.

“It is long past time that things did change.”

Addressing the minister, she added: “You have the opportunity to do that through a full robust inquiry into what happened so we do not repeat continuously the mistakes of the past.”

Mr Nesbitt responded: “I am deeply, deeply, deeply uncomfortable with what has happened. The public purse deserves much better.

“Speaking frankly, I’ve called a number of very challenging discussions about what has happened and about the best way forward.

“In fact, there was a very tense meeting in the department earlier this morning.

“I want to know how all this happened, what went wrong, what was done, what was not done.

“The Belfast Trust needs to determine what happens next to put all this right.”

The new maternity hospital is several years overdue and well over budget.

A Northern Ireland Audit Office report earlier this year said the hospital was originally expected to be completed by the end of 2015.

Three babies died during a previous outbreak of the bacteria at Belfast’s Royal Jubilee Maternity Hospital in 2012.