Flu rates three times higher than last year as dominant virus mutates

New Zealanders are catching the flu at three times the rate of last year, as the dominant strain of the virus begins to mutate.

Hospital emergency departments have seen a spike in admissions for influenza-like illnesses during July, with scientists hoping it is not related to a mutation in the Influenza A virus.

Auckland City Hospital said it had had the "busiest July ever" this year, with 136 influenza hospital admissions – up from just 41 in July last year.

Wellington has also seen more admissions in July, with 96 patients with influenza-like symptoms treated in Wellington Hospital alone.