It has been revealed that there are 997,258 patient appointments outstanding in the first six months of 2018.
An analysis of various health waiting lists revealed the substantial number of outstanding appointments in the first half of the year.
Over half a million people (511,415) were waiting on outpatient appointments in June 2018 while a further 135,000 were waiting on diagnostic appointments in April.
Primary care appointments - including psychology, dietetics, podiatry, ophthalmology and audiology - make up 63,496 of patients.
As of May 2018, 6,118 elderly persons were waiting for Home Support Hours while 3,850 patients were waiting for Assessments of Need under Disability Act in June.
Fianna Fáil Deputy Leader Dara Calleary has described the situation as a national scandal.
"The vast majority of this list is based on the National Treatment Purchase Fund monthly waiting times. In June 2018 some 717,419 were on the lists compiled by the fund," said Deputy Calleary.
"However the NTPF does not publish waiting lists for a number of diagnostic scans and the latest available figures (April 2018) showed a further 135,000 waiting for MRIs, ultrasounds and CT scans.
"There are also significant waiting lists for community care. There are 37,229 people waiting for either speech and language therapy or assessment in June 2018.
"A further 31,361 were waiting for an occupational therapy assessment in the same month. The HSE however was unable to provide figures for the number of people waiting for actual occupational therapy treatment.
Deputy Calleary said that there needs to be investment in capacity if there is to be any improvement in the situation.
"The ESRI has projected that demand for public hospital services could increase by up to 37 per cent for inpatient bed days by 2030.
"The time for grand plans, staged strategies and PR launches is over, what we need now is action."