Hospitals are struggling to cope with a big increase in the influx of patients attending A&E departments in recent days, pushing up trolley figures to their worst level since last March.
The cracks in the HSE's winter plan began to show yesterday as 606 patients were on trolleys waiting for a bed.
The worst-hit hospitals were University Hospital Limerick with 59 people on trolleys and South Tipperary General Hospital where 50 patients were without a bed.
Cork University Hospital also endured another day of severe overcrowding with 48 on trolleys.
The HSE said hospitals are seeing a surge in patients attending A&Es and more are having to be admitted.
The rise in patients struck by the flu, many of whom are ending up in hospitals and need to be put in isolation is also fuelling the congestion.
The number of bed blockers, patients fit for discharge who cannot be discharged without support, has also climbed again to 526, up from 469 on Christmas Day.
The figures come from the Irish Nurses and Midwives Organisation (INMO) which counts patients across the hospital who are on trolleys waiting for a bed.
These patients are often being treated on trolleys in corridors, but they may also be on chairs, in waiting rooms, or "simply wherever there's space", said the union.
It comes as the INMO meets health officials today to discuss their threatened all-out strike on January 30 in pursuit of increased pay which it says is needed to address recruitment and retention of nurses.
Hospitals still have more than 300 homecare packages to offer patients in a bid to free up beds in the coming weeks.
Commenting on the escalation, Health Minister Simon Harris said he acknowledged the numbers on trolleys were very high but insisted he always knew the surge would come.
"The surge was always going to come and we have seen a surge in relation to attendances in the health service, in particular in recent days," he said.
He said that because hospitals were so busy, the focus period of two weeks was now being extended for another fortnight.
This means the extra funding allocated for the winter plan will be concentrated into relieving pressures over the next two weeks.
However, it will also mean that more waiting list surgeries will be cancelled as efforts to keep overcrowding take priority.
He said: "My advice to the public remains the same: please keep the emergency departments for emergencies. If you do find yourself with a condition, check out undertheweather.ie, in terms of how you can best manage your own condition at home perhaps rather than spreading infection."
Meanwhile, pregnant women are being warned they are at higher risk of complications and should get the flu vaccine.
The swine flu which is currently circulating can have a particular impact on a pregnant woman who has a weaker immune system, the body's defence against infections.
The advice is that the best way to avoid getting flu is by getting vaccinated.
The flu jab protects both mother and baby. Flu can also be serious for newborn babies, who can catch the infection from their mothers. Complications can include bronchitis.