An electric scooter was seen crumpled in the middle of the road, with shoes and clothing scattered nearby.
Cordons were earlier put in place on Mayoral Dr near the intersections with Greys Ave and Cook St, as well as at the intersection with Hobson St and Cook St.
St John responded with one ambulance and one rapid response vehicle.
A spokesperson said one patient was assessed at the scene by the ambulance crew and was transported to Auckland City Hospital in a critical condition.
Motorists were asked to avoid the area if possible.
The cordons were lifted around two hours after the crash, with traffic able to use the central city roads just before 9am.
The Serious Crash Unit is conducting a scene examination and said the crash investigation will continue, the spokesperson said.
This morning at the cordon, officers blocked off a section of four normally busy downtown Auckland streets.
An intersection on Mayoral Dr, Auckland, has been cordoned off after a serious accident involving an e-scooter and a car this morning.
Around a dozen police were at the Mayoral Dr intersection where the accident happened, piecing together movements of both vehicles prior to the collision.
