“From the period that we have worked without an assembly, our nurse vacancy in that period doubled,” said Pat Cullen, the director of the Royal College of Nursing, “simply because we had no decision makers in place, no one in charge, no political leadership and everything was just in a state of inertia.”

Northern Ireland has the highest rate of nurse vacancies in the United Kingdom, at 14 percent — the equivalent of about 2,800 nurses absent from work each day. Ms. Cullen says the gap has placed huge pressure on nursing staff, who are presenting with mental health issues and sickness resulting from trying to fill the empty slots.

“They are not able to switch off, because as soon as they get home the phone starts to ring, and a manager is begging and pleading with them to come in the next day and fill in for someone,” Ms. Cullen said. “They never get a break.”

“Then, when they get to work,” she said, “they are having to care for the patients that are in the 24 beds within their ward, but finding that there’s another four or five beds lined up on the corridors.”

Northern Ireland’s health service is also struggling to cope with hospital waiting lists that have expanded to record levels. About 300,000 people are waiting for treatment, according to figures published by Britain’s Department of Health.

More than 100,000 people have been on a waiting list for over a year for surgeries like hip or knee replacements, Ms. Cullen said.