GP's Northern Ireland flu warning
A Londonderry GP has warned that more people in Northern Ireland are likely to be affected by the influenza virus over the next two to three weeks
Dr Tom Black said the situation over the Christmas period was "manic" due to two bugs - the norovirus and influenza.
He said extra surgeries had to be put on to cope with the number of patients.
The GP said while the norovirus incidents had started to decrease, those of the flu had not yet reached their peak.
"Our public health people track these and they reckon that around week 51 or 52 we were beginning to see a dip in the norovirus," he said.
"The influenza appears to be influenza B and it's only peaking, so it will increase in the next two or three weeks.
"The good thing is that we have vaccinated about 300,000 people for the influenza virus, so the most vulnerable will have turned up and had their vaccines."
Dr Black said the combination of the two bugs has led to an extremely busy Christmas for GPs.
"We've had to put extra surgeries on and I spoke to one of the out of hours managers and he described the situation as manic," he said.
"They saw in Western Urgent Care - which is the out of hours service for the west - more than 1,000 patients or consultations in one day, that was the Saturday before Christmas.
"Over the 10 days up to the end of the year, they saw more than 6,000 patients. The patients coming in to me were describing whole families down with one or other of the bugs.
"We would reckon that GPs in Northern Ireland over those 10 days saw probably about 200,000 cases in total."
The Public Health Agency said seasonal rises of the norovirus were to be expected approaching midwinter and this year was no different.
However, the PHA's Dr Louise Herron added: "It may be that although people have the symptoms of the nororvirus we're just not hearing about them because they're not presenting to their GP and they're not submitting samples.
"So we're aware with any kind of illness that we only really know about the tip of the iceberg."