The crash has also affected powerlines in the area and as a result a section of Swanson Rd had been closed off.
Auckland Transport issued an alert at 11.20am advising motorists of the closure. Officials said the road would be closed "for some time today".
"Avoid the area or allow extra time for diversions."
Police confirmed that the crash involved one vehicle.
Officers are in the area helping with diversions that have been put in place at Brick St and Rathgar and Swanson Rds.
"Motorists are advised to take an alternative route and expect delays."
The crash came just over an hour after another serious crash on the other side of the city on Massey Rd in Māngere.
Two people suffered serious injuries in a crash reported about 9.30am.
A St John spokeswoman said two people were taken to Middlemore Hospital. Both were in a serious condition.
Police said part of the road is closed in both directions and diversions are in place.