A St John spokesman said two people with moderate injuries were taken to Dunedin Hospital emergency department.
A police spokeswoman said police were called to the Dunedin crash, which involved two cars, at 9.23am.
Emergency service officials said two small cars collided on top of the bridge, at the point where eastbound vehicles turn left, to head north on Wharf St, or to turn right and head south along another section of Wharf St, towards Portsmouth Drive.
A St John spokesman said two people with moderate injuries were taken to Dunedin Hospital emergency department.
It is understood that both lanes of the southbound offramp were initially blocked off, but were reopened, apparently about 11am.
A police spokeswoman later said no further details about the extent and duration of the traffic disruption on the bridge were available.
Senior Station Officer Mark Leonard, of the Central Fire Station, said firefighters worked with St John Ambulance staff to help one injured person from one of the vehicles, but no cutting work was required.
Two fire appliances, from the Central and Willowbank stations had attended, and firefighters had also helped with traffic control duties, he said.
