The fire service's rope rescue team is on the way to an incident on Great North Rd, in the Waterview Tunnel area, where a person is understood to have fallen from a height.
Northern Fire Communications' shift manager Jaron Phillips said just after 4pm that a dozen firefighters were on their way to the scene, including a high angle rescue team.
He referred further comment to St John Ambulance.
An ambulance spokeswoman would not give details about what happened.
She did confirm that the person was transported to hospital and treated for moderate injuries.