Pregnant women, people aged 65 and over, and people of any age with long-term health conditions such as heart disease, stroke, diabetes, respiratory disease including serious asthma, kidney disease and most cancers are eligible for ''the jab''.
Although flu symptoms are similar to the common cold, they tend to be more severe and last longer.
Flu symptoms include sudden high temperature, headache, general aches and pains, tiredness and sore throat. Symptoms can make the sufferer feel so exhausted and unwell they have to stay in bed and rest until they feel better.
Public Health South Queenstown medical officer Derek Bell said the flu was far more serious than a cold and highly contagious. It could affect anyone, no matter how healthy or fit.
''This is why it is important to get the jab so that as well improving your chances against getting the flu you also avoid spreading it to the people you care about, your family members - especially the old and young - your friends, work colleagues and clients,'' Dr Bell said.
''We encourage all people to consider getting vaccinated and would like to remind certain groups that they can have the influenza vaccine free of charge.''