The HSE chief executive has said he is preparing for a "worst possible scenario" for the health service this winter.
Paul Reid says this would involve a "difficult winter season" and a resurgence of Covid-19.
He will tell the Oireachtas Covid-19 committee today that the HSE is hoping to avoid this scenario - but is carefully planning for it.
Virus expert Professor Gerry Killeen, of UCC, says a combination of flu and Covid pandemics this winter would be a disaster.
Prof Killeen said: "That could be a really tough scenario, as much in terms of non-Covid services as much as anything else, these are hugely important. I think that all of those concerns are completely valid, it's something we should mitigate and ideally avoid in every way that we can."
The warning comes as 110 people were being treated for Covid-19 in Irish hospitals on Sunday, with 18 in intensive care.
This is the highest number of patients with the disease in hospital since June 8th.
There were no further deaths and 390 additional Covid-19 cases confirmed by the Department of Health yesterday.
Of the cases notified yesterday, two-thirds were under the age of 45. 36 per cent are confirmed to be associated with outbreaks or are close contacts of a confirmed case, while 45 cases have been identified as community transmission.
209 of yesterday's cases were located in Dublin, 27 in Cork, 22 in Donegal, 21 in Galway, 14 in Kildare, 14 in Monaghan, seven in Roscommon, seven in Tipperary, seven in Waterford, seven in Wexford, six in Limerick, six in Longford, five in Laois, five in Meath, five in Offaly, five in Sligo, with the remaining 23 cases spread across eight other counties.
