He said the country crossed the threshold for "flu season" in late June and NDHB saw a spike in its provincial cases.
"Influenza season is now in full swing and for approximately the next 12 weeks, we are going to see increased numbers with the disease."
He said almost every winter the intensive care unit fills up with patients with severe influenza infections, many of them pregnant women and he expects this winter to follow the pattern.
"We are certainly seeing an increase of influenza presentations - and we have one person who is critically ill in ICU with influenza."
Mr Potts said the DHB had 14 type A influenza admissions and 10 type B influenza admissions in July.
The hospital is also seeing the Respiratory Syncytial Virus (RSV) which usually affects children also affecting older people, he said.
RSV is a very common virus which leads to mild, cold-like symptoms in adults and older healthy children. It enters the body through the eyes, nose and mouth
Mr Potts said people in the waiting room are assessed within 10-15 minutes of arrival by a nurse. Urgent cases are seen as soon as possible but non-urgent patients could wait up to six hours.
Waikato Hospital emergency department clinical director John Bonning told Radio New Zealand its wards were packed, and they were forced to keep people waiting in ambulances.
Mr Potts said this was not happening in Northland.
Alongside the DHB, St John is also reporting an increase in calls during the winter months.
Emergency calls to 111 for an ambulance increased by 6 per cent in Northland in June, up 6 per cent for the same month last year.
In June 2016 there were 1288 calls and in June this year, 1371.
Nationally the figure is up 8 per cent, from 40,900 calls in June last year to 44,200 calls in June this year. Most of these are due to flu and respiratory illness.
Acting district operations manager for Northland Ben Lockie said the service is "run off our feet" responding to calls.
"We are definitely seeing an increase in influenza symptoms and respiratory illness beyond last winter."
Mr Lockie said winter related illnesses always hit elderly hard, but he is seeing other age groups also affected by winter illnesses.
July and August are traditionally St John's busiest months where responses nationally are likely to increase from an average of 1170 incidents a day to 1333 a day.
Last week the service experienced its busiest week ever - responding to an average of 1373 a day nationwide.
Northland DHB's tips to avoid the flu:
- See a doctor when you start to feel unwell rather than waiting until you are really sick
- Have the influenza immunisation - especially if you are pregnant or elderly
- Influenza immunisation is FREE for those most at risk - pregnant women, those 65 years and older and those with chronic illnesses
- Influenza can affect anyone, no matter how fit, active and healthy
- Free GP visits for children up to their 13th birthday
