A "mini-whirlwind" has lifted the roof from a West Auckland factory, dumped it on power lines and cut electricity to the area, Fire and Emergency says.

Fire and Emergency shift leader Craig Dally said they were alerted to reports of an explosion in Henderson Valley Rd just after 4.30pm.

But the incident was actually said to have been caused by a weather event.

"A mini-whirlwind lifted the roof of a factory and that came into contact with power lines ... it sounds like it did spark because we were called to an explosion."


No one was hurt.

Two crews, one from Te Atatu and the other from Glen Eden, went to the scene, but only one remained on site.

A Vector spokesman was not immediately able to confirm how many customers were affected by the outage, but the electricity provider's app indicated it would not be restored until 8pm.

No one from the factory affected was immediately available to comment.