The Ministry of Health is considering reducing New Zealand's swine flu alert level because the number of new cases is falling.
"It's basically a de-escalation," deputy director of public health Dr Fran McGrath said yesterday.
"The general picture does seem to be a general trend of a decrease in influenza activity in recent weeks."
The monitoring system run by the Institute of Environmental Science and Research shows three weeks of a steep drop in the number of cases of all influenza-like illness reported by "sentinel" GPs, followed by a slight rise in the week to August 16, the latest period reported.
ESR says swine flu has become the predominant influenza virus circulating this winter.
The ministry said the number of reported deaths in which swine flu was a primary cause rose to 16 yesterday - an increase of one - after the death of a Waikato woman who had underlying medical conditions.
The official tally of people infected with the virus since it reached New Zealand in April was 3106 yesterday, but no one knows how much higher the true figure is since only a minority of potential cases are tested.
Dr McGrath said that although the national trend of influenza-like illness was now downwards, there were fluctuations in some regions and in some age groups. It was too soon to be able to say that a first wave of the swine flu epidemic was over.
"We would expect numbers of cases to continue over the coming months because that's what tends to happen with any influenza; even in the summer months we get cases of influenza."
She said all district health boards which had set up community-based assessment centres to handle swine flu cases had closed them and the number of swine flu cases being admitted to hospitals was falling.
Health authorities were using the reduction in case numbers to prepare for another possible increase.
As well, they wanted "to be even better prepared than we were last time", in case the swine flu virus mutated into a more virulent form that caused a more severe, second epidemic wave.
Plans remain uncertain on mass vaccination against the virus.
Dr McGrath said a meeting at the World Health Organisation next month would decide whether a vaccine against the virus would be included in the seasonal flu vaccination mix for the next southern hemisphere winter.