The CUH has put in place visitor restrictions at the hospital to contain the spread of the flu virus.
Management said the hospital has been exceptionally busy in recent days.
In the past week, 1,344 patients presented to the emergency department for review and treatment, of which 540 required admission.
"The increase in attendance is due to the large number of very ill medical patients requiring admission and a number of patients presenting with Flu symptoms," the CUH said in a statement.
"In the interest of patient care visiting restrictions have being put in place at the hospital. All infection control measures are in place and every effort is being made to manage and contain the spread of flu."
Elective surgical procedures have not been deferred.
Figures from the INMO show that more than 80 people were awaiting beds at Cork hospitals today.
Sixty-one people were waiting on trolleys and wards in Cork University Hospital along with 25 in the Mercy.
The spike in the numbers awaiting beds comes after the HSE warned of an increase in admissions as the flu season begins to ramp up in the coming weeks.
Speaking to the Echo, Dr Fiona Ryan, of the Department of Public Health in HSE South warned that while the flu is a mild illness for some it can be very serious and even cause death for others.
Her warning comes just days after the Echo revealed two people have been hospitalised in Cork University Hospital with swine flu, also known as Influenza A (H1N1).
The HSE’s influenza monitoring system involved collecting information from GPs, hospitals and laboratories across Ireland.
“All of these indicate that the flu season is about to take off,” Dr Ryan warned.
“This is what we see every year, a slight increase for a few weeks and then it goes up very quickly.
“Usually it stays up for a few weeks and then goes down again,” added Dr Ryan.
“All indications are is that it’s on the up.” Dr Ryan admitted there is concern that people with the illness will attend their GP or Emergency Department (ED) and cause further spread.
She said the flu season will lead to an increase in hospital admissions, particularly for those at risk or with chronic illnesses.
She urged people to avoid attending their GP or Emergency Department unless absolutely necessary and to call ahead if planning to do so.
Dr Ryan also urged people in at risk groups such as the elderly, those with long term illnesses, healthcare workers and pregnant women, to get the vaccine, which has been developed to combat this particular strain.
She also called on carers and family members of those at risk or with illnesses such as cancer, to get the vaccine.