After a deadly bacterium took life of three babies, the source of infection is being located by the hospital staff at the maternity unit of the hospital.
The deaths that happened at the Royal Maternity Hospital in Belfast happened due to a bacterium called pseudomonas and as a preventive measure; samples from other babies have also been taken.
Deep cleaning will be done at the area where they were being treated. Worried relatives will be assisted with a helpline that has been established.
The same infection caused the death of three babies in two weeks and following this yesterday a neonatal intensive care unit was being cleared.
Lungs, gut and skin can be affected by the bacterium which is called pseudomonas aeruginosa.
Women who have been admitted at the hospital and have higher chances of giving birth to premature babies will be admitted to other hospitals in Northern Ireland, the Irish Republic or Britain.
Colm Donaghy, chief executive of the Belfast Health and Social Care Trust, said, "The `first priority' was the safety of the babies and ensuring the work that we do keeps babies safe. A full investigation was being carried out."