A new strain of influenza has hit New Zealand and this year's vaccine provides no protection from it.

The Ministry of Health says the "influenza surveillance system" discovered the new strain of mild flu this month in the Waikato.

It has been identified as the Influenza B/Hong Kong virus, which has been in Asia for 15 years and was widespread in the Northern Hemisphere during its winter.

Ministry spokesman Dr Lance Jennings says that although the virus is not covered by this year's vaccine, its discovery should not cause alarm as influenza B viruses generally cause milder illness in elderly and high-risk adults.

The ministry has released figures showing a rise in the number of people visiting their doctor with flu-like symptoms, indicating that the flu season has begun.

More people than last year have opted to be vaccinated and the ministry is urging even more to get the jab as winter sets in.

Until the end of June the ministry is paying for vaccinations for people aged 65 years and over, as well as for people with certain chronic medical conditions. Dr Jennings says that for some people with chronic illnesses, flu can trigger serious complications such as pneumonia, which can lead to hospital admission or death.

Last year, more than 48,000 New Zealanders caught the flu.

nzherald.co.nz/health