Ambulances only managed to respond on time to life-threatening calls in just under a third of cases last year.
The delays in adhering to expected response times are being highlighted in a Prime Time exposé on RTÉ tonight.
Investigators report on how patients in emergency situations are left waiting up to an hour for paramedics to arrive, and how some parts of the country have no ambulance cover whatsoever.
Dylan Berry's father Dan died last year at his home, three minutes from Wexford General Hospital:
"If I had been told on the first phone call that the ambulance was coming from Enniscorthy, I think my whole pattern of thought that morning would have been different.
"More likely what I probably would have done was got my dad into the car and … I would have been over to the hospital in three or four minutes. Less."
The ambulance service has declined to say how many of its rapid-response vehicles – expensive Subaru Forester SUVs – are used by paramedics and how many are in use by managers.
A spokesperson previously told the Irish Examiner: “All vehicles purchased in 2013 and in previous years, which are used by managers/paramedics/advanced para-medics are in daily use and are available to respond to emergency calls as and when required.”
Paramedics, however, maintain that these vehicles were often brought home by staff.