WorkSafe has launched an investigation into an incident this week where a man digging a hole struck a high-voltage underground cable and suffered an electric shock.

The man was digging the foundation for a sign on Te Ngae Rd in Rotorua on Tuesday morning when he came into contact with a Unison cable and was airlifted to Waikato Hospital intensive care unit in critical condition.

He is currently recovering in hospital a spokesman confirmed today.

Earlier in the week WorkSafe said they had made initial inquiries, but today confirmed they had opened an investigation into the incident and couldn’t comment further while the investigation was ongoing.

A worker came into contact with underground cables while installing a sign on Te Ngae Rd in Rotorua. Photo / Andrew Warner.

An investigation can take up to 12 months to complete, a spokesperson said.

The injured man is a “long-time” employee at Directionz, a signs and road asset installation company.

General manager Stephen Lincoln told the Rotorua Daily Post earlier this week that the incident involved a transformer and the person had hit a “high-voltage cable” while digging the foundation for a sign.

Unison relationship manager Danny Gough said Unison staff weren’t involved in the work being carried out when the incident happened but were called to the scene after the incident to secure the area and make it safe.

A Hato Hone St John spokesman said two ambulances, one helicopter, and one rapid response vehicle were sent to the scene.

- Rotorua Daily Post