One of the five ambulances serving Fermanagh has been on the road for nine years and has over 200,000 miles on the clock. The other four vehicles in the County all have over 100,000 miles on the clock.
The worrying figures were revealed by the Department of Health following an Assembly question from South Down DUP MLA, Jim Wells.
The figures show that 55.3 per cent of the Northern Ireland Ambulance Service (NIAS) fleet is over five years old, and that 12 of the ambulances, including one in Enniskillen, have been on the road for nine years.
Mr Wells said it raised serious questions about the capacity of the ambulance fleet to respond to emergencies 'in a satisfactory of speedy manner'.
He went on: "Some of the figures revealed in the minister's response are truly staggering.
"In Dungannon, one emergency ambulance has 312,759 miles on the clock. Indeed, in Ballymena, Ballymoney, and Ballycastle, there isn't a single ambulance with less than 100,000 miles, while in Fermanagh four out of five ambulances have more than 100,000 miles registered, with one recording nearly 206,000 miles."
Responding to the claims, the NI Ambulance Service have already said the situation 'is less than ideal'.
In a statement, it said the Service operated a fleet of 307 vehicles, including 132 Accident and Emergency ambulances which covered in excess of five million miles a year.
The organisation said they ensured regular maintenance work was carried out in the fleet, and that 'unplanned breakdowns are dealt with as quickly as possible'.
NIAS stressed it was important that the figures were set in context, adding: "In 2007/08 NIAS responded to 111,000 emergency calls, which was an increase of eight percent on 2006/07.
"NIAS also improved its response performance by reaching 69 per cent of Category A (immediate life threatening) calls within the eight minute target in February 2008, compared to a performance of 55 per cent in 2006/07."
The DUP Assembly member for Fermanagh/South Tyrone, Arlene Foster described some of the findings in the Report as, 'truly staggering'.
"This information raises serious questions about the capacity of our ambulance fleet to respond to emergencies, such as road accidents or house fires in a satisfactory and speedy manner," she said
"Th question was specifically confined to the emergency ambulances that would deal with this type of situation rather than the ambulances which, for example, transport older people to hospital to attend Out Patients appointments, in order not to confuse the information supplied by the Minister".