The Malta union of Midwives and Nurses has declared an industrial dispute at Mater Dei Hospital over a lack of personnel for constant watch on patients.
Constant watch is prescribed by doctors in particular circumstances, such as when there is a danger that a patient might harm himself.
The union said a shortage of carers meant that the support staff of nurses was being depleted for constant watch purposes.
Not carrying out constant watch as prescribed by a doctor meant a reduction of safe practices.
The union said it could also not tolerate a situation where its members ended up embroiled in legal issues because a patient supposedly under constant watch fatally injured himself or escaped from hospital.