The Northland District Health Board is advising people, especially pregnant women, to get immunised against influenza as they were a priority group when vaccine supplies ran low.
ESR figures show 47 percent or 23 out of 48 patients tested by their GPs in Northland between April 21 to June 9 returned a positive result for influenza.
Graham said vulnerable group such as people over the age of 65 and those prone to sickness were likely to suffer from the non availability of flu vaccines.
"The strain of flu seem to be getting worse but the government is not funding their medicines."
The Ministry of Health is asking GPs and pharmacies to ensure flu vaccine stock is closely managed and to prioritise the vaccination to those at greatest risk, including pregnant women, children under 4 with serious respiratory illnesses and those over 65.
Those with severe asthma, heart disease, diabetes and other serious health conditions that make them susceptible to flu are also at risk.
The ministry said already this season, distribution of influenza vaccine in New Zealand has reached near-record levels, with around 1.3 million doses distributed so far this winter.
"The ministry has asked providers to prioritise the stock remaining in clinics, estimated at around 20,000 doses, to those most at risk from the harmful effects of influenza."
Pharmac and Seqirus have worked together to make 14,000 vaccines originally intended for the private market available to those who were eligible for publicly funded vaccines, the ministry said.