Emergency services are responding to an incident at Wellesley St in Auckland.
Police were called at 6.15pm to an incident in central Auckland at the Wellesley St motorway overbridge, Grafton, a spokesman said.
A witness said around six police cars are at the scene.
A person has been transported to Auckland Hospital with critical injuries.
Parts of the motorway were closed for a time while police responded but are now open.
Police thanked motorists in advance for their patience if they experience delays in the area.