Northern New Zealand was on tornado watch today but as of late afternoon none had struck.

A severe thunderstorm outlook issued by MetService yesterday included a warning of possible tornadoes, three days after one person died in a tornado that wrought havoc on Auckland's North Shore.

The trough was extending from near Auckland to Taranaki and "becoming reasonably active" by 5pm, MetService chief forecaster Peter Kreft told NZPA.

"It's moving at about the speed we expected it would yesterday. You might say everything's on track," he said.

"But I'm not aware of any occurrence of tornadoes."

Mr Kreft yesterday said the predicted weather patterns ticked all the boxes for tornado potential but it was difficult to predict the likelihood, location or timing of any possible tornadoes.

The severe thunderstorm outlook applies until midnight tonight.

Mr Kreft said more unsettled weather was predicted for the weekend, though not with tornadoes.

"As a system bringing thundery showers it too will have a little bit of get up and go."