While there has been a sudden rise in influenza cases in some regions, Otago and Southland are not showing a high rate of infection.
Otago-Southland medical officer of health Dr Marion Poore said an increase would usually be expected in flu cases in the south from the end of this month.
The latest ESR data gathered from a selection of general practices throughout the country shows the consultation rate for influenza-like conditions has almost doubled in the past month.
The Bay of Plenty District Health Board area had the highest consultation rate at 184.3 cases per 100,000, followed by Nelson-Marlborough and Auckland.
In the Southern area the rate was under 40.
In the Southern area there had been under five laboratory-confirmed viruses in the first 28 weeks of the year, among the lowest in the country.
Dr Lance Jennings, a virologist and spokesman for the National Influenza Strategy Group, said that all three types of influenza virus in circulation - pandemic HINI 09 (swine flu), H3N2 and B virus - were covered by the 2011 season influenza vaccine.
Dr Poore said eligible people had until the end of the month to get a free vaccination from general practices.
