A tornado reportedly touched down in Waikato for about 10 minutes this afternoon, with a local farmer sending a photograph to forecaster WeatherWatch.co.nz.
The picture was taken at Paterangi, just south of Hamilton.
While tornadoes weren't in the forecast today, unstable and slow conditions had led to the funnel cloud and then short-lived tornado, head analyst Philip Duncan said.
It was at the lowest end of the scale but was still capable of lifting pieces of roofing iron and breaking branches.
Mr Duncan said funnel clouds may be spotted over the next couple of days, along with short, sharp, squalls which are similar to tornadoes but don't spin.
"This looks like a bit of a one-off as the north of New Zealand is still very much in a humid, mild, pool of unstable air - overnight it becomes more unstable but the air will get much colder and that limits the chances of further tornadoes" he said.