Dublin Fire Brigade was understaffed for over 2 out of every 3 days in September.
One particular day saw the service 45 members short of what's required.
According to Freedom of Information figures Dublin Fire Brigade was understaffed for 23 out of the 30 days in September.
The minimum number of staff needed for daytime shifts is 180. That includes all frontline staff and staff in the control centre.
The 10th of the month saw the service stretched the most, with 6 fire appliances off the road and 135 staff out of the 180 on duty.
Staffing issues also saw ambulances taken off the road. There were 2 ambulances each on the 7th and 27th without crews.
Dublin Fire Brigade says it takes the health and safety of its staff and the public very seriously.
It also says 80 recruits have passed out of its training centre since January this year, with a further 30 expected to become operational in the coming weeks.
The service is also currently advertising a new recruitment drive for firefighters.