An arcing power line caused an explosion that was heard in Northcote, on Auckland's North Shore, this morning.
A staff member at Northcote Preschool said they heard an explosion about 10-15 minutes ago.
"It was just a great big, huge bang," she said.
"We weren't really sure what it was and we looked outside and couldn't see anything."
A northern fire spokesperson said crews have now left the scene at Lake Rd and power has been restored.