The level of hospital overcrowding reached record levels in August, according to the Irish Nurses and Midwives Organisation.
It says there were 7,781 patients on trolleys or on wards last month, waiting for admission to a bed, up 27% on the same month last year.
The figures were released in advance of a meeting today of the Emergency Department Task Force, to review the summer and prepare for the autumn/winter period.
The hospitals worst affected by overcrowding last month were: Limerick University Hospital, Galway University Hospital and South Tipperary General.
INMO General Secretary Liam Doran said that in view of the figures, the union would be seeking senior decision makers to be rostered, on an extended day basis, over the seven days of the week.
He said he also wanted nurse managers to be given full autonomy to recruit extra staff to ensure patient standards are maintained.
The union also said that senior general managers should be present in the hospitals on a 24/7 basis.
Mr Doran said that the level of attention required to manage the trolley crisis had dropped in recent months.
Today there were 357 patients on trolleys or on wards waiting for admission to a bed.
The INMO figures show the hospitals worst affected are: Limerick University Hospital with 44 patients waiting, Galway University Hospital with 28 patients and Letterkenny General Hospital with 23 patients waiting.
The HSE says demand for emergency department treatment and care continues to grow.
By the end of July, over 720,000 patient attendances were recorded in emergency departments - a 2% increase compared to the same period last year.
It said the number of patients aged 75 years and over attending emergency departments increased by almost 5%.
The HSE said the number of patients on hospital trolleys awaiting admission to hospital wards from emergency departments decreased by 1.4% in the year to date.