New figures show more than 776,000 patients were waiting for a public hospital appointment as of the end of last month.
The Irish Hospital Consultants Association (IHCA) says the figures from the National Treatment Purchase Fund (NTPF) show a 46,500 increase in total numbers on waiting lists since January 2019.
More than 52,700 children are waiting for care at the three children's hospitals that are part of the Children's Health Ireland hospital group.
While the number of patients waiting for essential inpatient care is over 67,300.
The areas with the largest number of people waiting to access hospital care include orthopaedics, ENT, dermatology, ophthalmology, general surgery, urology and gynaecology.
The IHCA has said the figures "do not represent the full extent of adults and children waiting across Ireland" - as they exclude a number of patient groupings.
These include children seeking care in other hospitals not part of the Children's Health Ireland group - or adults and children awaiting diagnostics such as MRI or CAT scans, ultrasounds or x-rays.
The NTPF also said 18,036 patients are classified as 'suspended'.
This refers to those who are temporarily unfit or unable to attend due to clinical or personal/social reasons.
The suspension category is also used where patients are being treated through various insourcing or outsourcing schemes.
The NTPF has been given €100m in Budget 2020, an increase of €25m on 2019.
It said the additional funding will be used to "benefit patients throughout the country", while also increasing its focus on outpatients.
IHCA President Dr Donal O'Hanlon said: "Another year has passed by without any discernible improvement for patients in accessing our public hospitals.
"The figures continue to go in the wrong direction, which is unacceptable.
"The lack of capacity in our public hospitals and the consultant recruitment and retention crisis are the key factors in the long wait times patients face."
He added: "The next government must now listen to what voters want and quickly move to address the overwhelming capacity deficits in our public hospitals.
"Increasing beds and filling the over 500 vacant consultant posts must be urgently addressed to reduce the unacceptable waiting lists and provide timely quality care to patients".