Strong demand for flu vaccinations has resulted in treatment supplies running low.
More than 1.2million doses of vaccine have been distributed, but with the flu season now in full swing supply has failed to match demand, clinicians say.
The shortfall is a nationwide issue, but Southern District Health Board medical officer of health Susan Jack said those most at risk of catching the potentially fatal illness would still be able to receive a preventive injection.
"Those in most need are still able to get the vaccination including pregnant women; those aged 65 and over; children aged 4 and under with serious respiratory illnesses and people with severe asthma, heart disease, diabetes and other serious health conditions that make them more susceptible to influenza," Dr Jack said.
"It is encouraging that so many people have taken the opportunity to have the flu vaccination this season."
Influenza arrived early in New Zealand this season with several cases recorded before vaccine supplies arrived in the country.
Then an awareness campaign meant many of the available vaccine doses had been snapped up.
Ministry of Health deputy director of public health Harriette Carr told Pharmacy Today clinicians should know about limited stock.
"We'll continue to work with Pharmac on the possibility of sourcing new stock, and ... managing existing stock."
Dr Jack said measures to prevent the spread of what was a highly contagious disease were important.
"Stay at home if you're unwell and call your GP practice for advice first if you think you have the flu," she said.
"Do not put patients and colleagues at risk of picking up an infection."
