The HSE has said an urgent examination is under way after a second ambulance caught fire in the last week.
In a statement, it said a new community paramedic response vehicle, awaiting entry to service, went on fire in Tullamore, Co Offaly yesterday.
It follows an incident last Saturday where a recently commissioned emergency ambulance was destroyed by a blaze while parked at an ambulance station in Castlebar in Co Mayo.
Neither vehicle was in use at the time, and no patients or staff were injured, the HSE said.
It is also said the two vehicles affected are different makes, models, and types, and that an initial technical examination has identified "a possible issue", which is now being "urgently explored" in further detail with vehicle suppliers.
The statement also says that in line with health and safety requirements, all staff on duty have also been alerted to the two known incidents, and have been requested to "remain vigilant".
It said ambulance services to the public are unaffected by the current precautionary measures, which will remain under constant review
