There was a 31% increase in the level of overcrowding at the region's main hospital last month compared to the same time last year.
New figures from the INMO show 649 people were waiting for beds at University Hospital Limerick in July.
Despite this, there has been a decrease in numbers at Ennis General.
The Irish Nurses and Midwives Organisation says the latest figures confirm record numbers of admitted patients on trolleys compared to previous years.
649 people were left waiting for beds at University Hospital Limerick, up from 495 in the same month last year.
It represents a 605% increase in the level of overcrowding at the Dooradoyle facility in the past ten years.
The figures are in stark contrast with the overall national figure which shows a 1% increase in trolley numbers in July and a 95% increase in the past decade.
Nurses have pointed to the number of vacant nursing posts in the country’s Emergency Departments as part of the problem.
They say that despite a DOH/HSE commitment, as part of a national agreement, health employers have failed to fill all vacant nursing posts, which is now estimated to be over 150, up from 135 earlier this year.
Ennis General Hospital has seen a decrease in numbers however, with 10 people waiting for beds in July, compared to 19 the same time last year.
