A small tornado has reportedly touched down north of Auckland, as heavy rain sets in over the north of the North Island.
WeatherWatch.co.nz has received reports of a small tornado in Puhoi, just before midday.
A Fire Service spokesman said there had been no weather-related callouts today.
MetService have issueda severe thunderstorm outlook, as an unsettled east to northeast flow covers the central and upper North Island today.
Showers are expected to become heavier and more frequent over central and northern parts of the North Island this afternoon and early evening, with a low risk of thunderstorms.
However, the risk of thunderstorms is considered moderate over Northland this afternoon, and these thunderstorms may produce localised rainfall rates of 10 to 20mm/hr and small hail.
WeatherWatch.co.nz weather analysts say "very unstable weather conditions over the upper North Island could generate isolated small tornadoes both today and tomorrow along with isolated thunderstorms".
Heavy showers, some with thunder, may also cause localised flash flooding, WeatherWatch.co.nz says.
