SIPTU say there are no plans on how to deal with emergencies when firefighters strike next week.
Dublin Firefighters will strike on the 18th and 27th of March.
It's in response to ambulance 'call and dispatch' functions being away from Dublin Fire Brigade.
Over 200 firefighters, their families and supporters protested outside city hall on Sunday against the plan by Dublin City Council.
Local authority chiefs want to disband the Emergency Medical Service along with the call centre, and merge it with the HSE’s National Ambulance Service.
SIPTU's Brendan O'Brien says, "by removing Dublin Fire Brigade's call and dispatch you're building in delays into the system where there's no guarantee that if all of the ambulances are tied up and busy that fire appliances can be dispatched within the timely fashion that they need to be to save lives".