Health Service Executive Director General Tony O'Brien has told RTÉ News that he has "considerable confidence" in the national ambulance service and its leadership.
However, he said that nobody in the HSE believed the service is "where it needs to be" and significant change was already happening.
Mr O'Brien's comments follow last night's RTÉ Investigations Unit report on the service, which found just one in three people with life-threatening conditions were responded to by the ambulance service within the recommended target time last year.
It also showed that some emergency cars infrequently respond to emergency calls, particularly at night.
He said the HSE was open to "learning any lessons" that may arise, including telling callers how long an ambulance may take to reach them.
He also said officer response cars were an important facility that must be used effectively.
Speaking in Dublin this morning, Mr O'Brien indicated he had as yet not seen the full RTÉ Prime Time programme, but was aware of the general issues it raised.
He said: "We have already indicated that we have room for improvement in our ambulance service, and that is why we have been investing in it significantly over the last number of years, and why we're engaged in a major reform of the way our ambulance control functions work.
"Nobody in the HSE believes our ambulance service is where it needs to be, that's the first thing to say.
"There is a desire to increase the capacity of the ambulance service to respond more effectively, to use its resources as effectively as possible, and that work is under way and as has been outlined in the programme, that involves a number of changes around the way the ambulance fleet is used, the way the control centre functions, and those things are being rolled forward.
"There is no doubt in my mind that the ability of the ambulance service to respond more quickly to calls will improve."
When asked if callers should be given more information about the time an ambulance could be expected to reach them, Mr O'Brien said: "I think it is always important in healthcare that there is absolute candour and if there are limitations on the services that can be provided at a given time, callers should be made aware of those things and to that extent clearly we're very open to learning any lessons that present themselves."
He said the level of demand for the national ambulance service was increasing and "we need to examine every possible was to support the ambulance service to meet the changing needs of our population".
Director defends ambulance service
National Ambulance Service Director Martin Dunne has defended Ireland's ambulance service, stating the quality of care it delivers to patients is "second to none".
Speaking on RTÉ's Morning Ireland, Mr Dunne said staffing numbers have increased by 16% since 2008.
He said these figures show a commitment from both the Government and the HSE and he said the ambulance service is going through a huge change.
Mr Dunne said it has been given the finances and staff to deliver that change.
He said: "We are an ambulance service that is going through a huge change programme and we are working extremely hard with our staff. Staff have to be looked after.
"They have a massive training regime going on and the quality of care that we are actually delivering to patients is second to none. That much I'm very confident of."
Speaking on the same programme, the Chair of the National Ambulance Service Representative Association said the service is experiencing a lack of resources, lack of personnel and a lack of funding, which has resulted in response time targets not being reached.
Michael Dixon said staff members who had been lost through retirement or leaving work had not been replaced.
Commenting on a cut in ambulance shifts in the west of Ireland, Mr Dixon said he believed this reflected the picture nationally.
He said: "Our members have raised this issue. We are certainly going through a lack of resources, a lack of personnel, and a lack of funding.
"This in itself has resulted in the fact that response times key-performance indicators can't be reached."