Nurses in Northern Ireland will go on strike over staffing numbers and pay disputes on 18 December, the Royal College of Nursing (RCN) has said.
The union said its members were planning 12 hours of strike action - the first in the RCN's 103-year history - having voted for the move last week.
There are more dates of strike action planned for the new year.
The health department said it remained "focused on finding a way forward" and was finalising a pay offer for 2019-20.
"This will be the best offer possible within the budget available, but the reality is that our ability to address pay issues is inevitably constrained at a time of intense budgetary pressures for health and social care services," said a department spokesperson.
The nurses' first day of industrial action, which includes refusing to do any task that is not patient-specific, will be on 3 December.
The industrial action will also include:
- Not working overtime
- Not working unpaid hours
- Not completing paperwork other than individual patient records
There are 2,484 registered nurses and 454 nursing support worker vacancies in Northern Ireland, according to the latest available statistics, which were published in June.
Nurses' pay within the health service also continues to fall behind England, Scotland and Wales, the RCN said.
The union said this was having a detrimental impact on patient care and adding pressure to the existing workforce.
In a ballot held over four weeks, 96% of nurses balloted voted in favour of industrial action, with 92% backing strike action. The turnout was 43.3%.
The total number of those balloted was about 8,000.
The RCN's Northern Ireland director Pat Cullen said after the vote that nurses had "spoken clearly".
The Department of Health said that, despite claims to the contrary, there was "no separate or untapped source of funding that we can access - nor can money simply be found in the budget".