The illnesses have come at a time when the ED was operating on a par with its busiest time of the year.
"You might expect for us to be seeing about 130-135 people through the door in a day. At the moment we are getting 140-160 at times, so it's certainly well up on most numbers. These are numbers we might expect at Christmas and New Year."
But Dr Sage said the team, through working longer shifts and overtime, was handling it.
"We are holding our own in terms of not needing extra staff but we are working flat out," he said.
"We are coping but it's really credit to the resilience of our staff to keep the service going in the face of the onslaught."
Dr Sage said last winter there was an 8 per cent increase on people coming through the ED doors. He suspected this year was a similar increase.
"We are not sure at the moment but we know that GPs are also facing increasing demand."
Dr Sage said demand on beds was such that they were required to open other areas of the hospital to fit patients in.
"There are areas of the hospital where sometimes we have to increase the number of beds to accommodate for that.
"If we find that we've got too many patients for the beds that we have, sometimes we flex and use areas of the hospital that we normally wouldn't use out of hours."
Dr Sage said if people who did not require ED help stayed home, staff could focus on people who really needed it such as elderly and vulnerable people whose respiratory conditions have been triggered by a virus.
These people were often admitted overnight instead of sent home.
People who were not vulnerable could expect to wait at least an hour or two in ED before they were seen, Dr Sage said.
"We have to prioritise who we see and when."
Earlier this season, medical authorities told the Bay of Plenty Times they were bracing for a winter illness onslaught.
Bay of Plenty medical officer of health Phil Shoemack said he expected peaks to happen in late June and September.
Camilla Wilkin, practice manager of BayMed which covers Bayfair Doctors, said they had been swamped with people seeking help for coughing, sore throats and general cold and flu-like symptoms. Extra staff had been rostered to help cope.