Emergency services are attending an incident around 100m off Ruakura Rd, close to Waikato University in Hamilton, after a temporary structure erected around a power pylon collapsed.
One person was trapped, but has since been rescued by emergency services. They are being treated at the scene by ambulance staff.
It is understood the pylon was a new pole for the expressway.
"It only just happened and we're trying to get to the bottom of it," a university spokeswoman told NZ Newswire.