Tallaght Hospital's newly- renovated emergency department will open in April.
The news comes after a 100-year-old woman spent 24 hours on a trolley in the hospital earlier this month because no ward bed was available for her.
The updated emergency department will double in size and have eight more major cubicles, two isolation rooms, eight ambulatory care cubicles and an extra triage space.
However, while the expansion is welcomed, there are concerns over staffing levels in Tallaght.
"We need to know that our hospital is safe. While it's positive that we have a new unit, if things aren't going to change then what's the point," said Fianna Fail councillor Charlie O'Connor.
"I'm certainly calling for staffing needs to be dealt with. I want assurances to the community that it's (staffing levels) are sufficient," he added.
Earlier this month, the Irish Nurses and Midwives Organisation released figures that showed Tallaght Hospital as being the second worst affected hospital in the country in relation to the number of patients on trolleys.
The current expansion of the emergency unit is part of a €5m two-phase project.
Also included in this project are two family bereavement rooms and a new psychiatric assessment unit.
The Herald understands that no specific opening date has been set in April.
"Work on Phase II is currently ongoing and the commissioning of the final phase is due to take place in April," said the hospital's spokesman.