The total number of people on hospital waiting lists now stands at over 707,000, the highest number recorded.
The latest figures issued by the National Treatment Purchase Fund are for last month, and are up by over 6,200 on the previous month.
The hospital with the biggest outpatient waiting list is Galway University Hospital with over 39,000 people waiting for treatment - of a national total of almost 52,000.
This means over 39,000 people referred by their GP are now waiting for treatment or an appointment with a consultant at UHG - with almost five and a half thousand of these patients waiting over a year and a half.
There are over 8,300 people on the outpatient waiting list at Mayo University Hospital, with one in four of these patients waiting over 18 months.
Sligo University Hospital has an outpatient waiting list of over 12,600 people, with 2848 waiting for procedures at Roscommon Hospital and 3646 at Portiuncla in Ballinasloe.
In addition, almost ten and a half thousand people are waiting for inpatient or day surgery at University Hospital Galway, where the combined waiting lists now stand at almost 50,000.
In a statement, Minister for Health Simon he recognises that the outpatient waiting list "remains a significant challenge" which he said the HSE and National Treatment Purchase Fund are working hard to address.