The industrial relations officer with the INMO for Beaumont Hospital has described the situation throughout the Medical and Surgical Departments as "extremely serious", saying staffing levels are very unsafe.
Speaking on RTÉ’s Morning Ireland, Lorraine Monaghan said it is impossible for staff to deliver safe patient care in that situation.
Ms Monaghan said this is why they have chosen to take industrial action.
92% of the Irish Nurses and Midwives Organisation's members voted in favour of strike action earlier this week due to overcrowding in emergency departments.
A work to rule will begin throughout the Medical and Surgical Departments on 16 December, which will see nurses refuse to carry out non-essential clerical and administration work until their situation is addressed.
Ms Monaghan said: "Our members are telling us that it is impossible to deliver safe patient care in these conditions.
"And they've been highlighting their concerns with management for a very long time, however, the situation has continued to worsen as nurses are leaving.
"So our members have been left with no choice but to take this action," she said.
In a statement, Beaumont Hospital said it had noted the result of a ballot by members of the INMO.
The hospital said it has been consistently working with the INMO regarding current vacancies and has developed a strategic recruitment campaign which targets nurses nationally and internationally.
The hospital said it has also partnered with a number of large academic teaching hospitals in Dublin as part of this recruitment campaign.
