The Irish Association for Emergency Medicine has rejected the Health Service Executive assertion that 50% of those on trolleys awaiting admission to a hospital bed have influenza.
The association has said the true figure is likely between 10-20%.
The latest HSE TrolleyGar figures show there are 329 patients waiting for admission to a bed - a 109% increase on the same day last year.
Last week, the HSE reported that half of people awaiting admission to hospital from emergency departments around the country had the flu.
Fergal Hickey of the Irish Association for Emergency Medicine said that while patients are presenting with influenza and a proportion of these will inevitably require admission, the actual proportion of those on trolleys as a result of influenza is between 10% and 20%.
He said there is an expectation that the situation may get worse, due to the lack of any surge capacity in the system and the lack of isolation facilities across the country.
Data from one of the main Dublin hospitals, St Vincent's University Hospital, put the flu cases on trolleys at about 7%.
Emergency medicine staff at Connolly Hospital in Dublin also said the HSE position regarding flu case levels was not being experienced there.
Former St James's Hospital Emergency Department consultant Patrick Plunkett said on social media that if was the case that 50% of patients on trolleys had the flu, it would be catastrophic.
The HSE is due to give a winter hospital service update briefing tomorrow.
The HSE said that a large number of current presentations to GPs, Out of Hours services and Emergency Departments are with conditions that are infectious, predominantly flu-like illnesses.
It said that as reported by hospitals to the HSE, 50% of patients awaiting hospital admission on Friday 27 December were in this group.
The HSE said that patients being admitted with infectious illnesses, require particular bed placement for infection prevention and control and this adversely affects patient flow in the already challenged health system.