The annual flu season is tracking well below a low rate of the disease, but more New Zealanders are testing positive to the illness than normal.
The most recent ESR influenza reports have shown a slight rise in cases of the disease over the past fortnight.
The prevalence of the disease has crept above the baseline seasonal level for flu cases, but remains well below a low seasonal level.
However, more people who think they have influenza - an illness with symptoms in common with many other winter ailments - are correct in their diagnosis.
"Over 45% of samples tested in GPs and hospitals this year are influenza-positive, which is one of the highest positivity rates for this period in recent years,'' an ESR statement said.
Outbreaks of influenza had been recorded in Nelson, Marlborough and Canterbury but in other regions, including Southern, indicators of severe cases were low.
Health Line calls were at the expected level, although up significantly on the previous week, but GP visits and flu presentations were down.
Hospitals were slightly busier with influenza cases, but numbers of patients were still low.
The Ministry of Health flu tracking programme, in its second year of operation, showed participants with fever or cold symptoms were down on the same time last year,
Two-thirds of the 4000 participants were vaccinated, and their rate of flu symptoms were below unvaccinated people.
New Zealand has run very low on flu vaccine and high demand has meant almost all doses have already been snapped up.
The Ministry of Health, which a fortnight ago asked doctors to prioritise at-risk patients for their remaining stocks, has found an extra 20,000 doses from vaccines intended for the private market.
A ministry spokeswoman said it was unlikely more vaccine supplies could be found as demand was an international issue, and Australia was also out of surplus stock.