New hospital waiting list figures show an increase in the number of adults and children waiting for inpatient, day case and outpatient care.
In total, over 490,500 patients are awaiting treatment or assessment in the public hospital system.
Galway University Hospital has emerged as one of the worst hospitals in terms of the numbers waiting.
The data from the National Treatment Purchase Fund covers the period to the end of last month.
It reveals there are 399,086 people waiting to be seen for the first time by a consultant at an outpatient clinic, having been referred there by their GP.
Over 6,100 are waiting over a year and a half to be seen.
There are also 72,881 patients waiting for inpatient, or day case treatment.
Over 1,200 are waiting over a year and a half to be seen.
A further 18,579 patients are waiting for a gastrointestinal check.
If all of these patient groups are added together, there are 490,500 patients waiting for treatment or to be seen at a clinic.
A spokesperson for Minister for Health, Leo Varadkar said that 300 extra hospital beds have been opened.
He said that by the end of last year, the targets for the shorter maximum waiting time of 15 months were met in 95% of inpatient cases and 93% of outpatient cases.
He added that the latest figures can be attributed to peak winter demand for emergency care and that Fine Gael is proposing a special €50 million annual fund for waiting lists.
Dr John O'Donnell, a consultant in Emergency Medicine at Galway University Hospital, has said unfortunately there has been no real improvement at the hospital, saying numbers are still up at the Emergency Department.
He said there is an average of 20 people on trolleys every day and staff and patients are fighting the system daily.
He added that the problem centres on resources.
A HSE statement said: "The key priority for the HSE is to tackle long wait times.
"The Service Plan 2016 sets out a number of key performance targets for hospitals in relation to waiting list management and these are set out below. Based on data from the end of March our hospitals are performing well against these targets."
It said that of the total numbers currently waiting, approximately 40% have been waiting less than three months and 5% are waiting more than 15 months.
The hospital with the longest waiting list for outpatients is Galway University Hospital, where there are over 30,454 waiting to be seen for the first time at a clinic.
Other hospitals with very long outpatient lists are: Beaumont Hospital with 26,255 waiting, the Mater Hospital with 24,597, Cork University Hospital with 24,179 and Our Lady's Children's Hospital in Crumlin with 12,267.
The hospital with the longest waiting list for inpatient and day case treatment is also Galway University Hospital where there are 10,605 patients waiting.
Other hospitals with very long inpatient and day case lists are: Beaumont with 6,251 waiting, the Mater with 5,798 waiting, St James's with 4,840 waiting and Our Lady's Children's Hospital Crumlin with 3,049 waiting.
The number waiting has increased in all categories - outpatients, day case and inpatient since the February figures.
The longest waiting lists for outpatients are in ear, nose and throat with 49,423 waiting to be seen, orthopaedics with 47,001 waiting and general surgery with 35,084 waiting.
Of the 72,851 waiting for inpatient or day case treatment, the longest lists are in ophthalmology.