The crash happened about 7.25am on Frankton Rd at the intersection with Middleton Rd.
A police spokeswoman said Frankton Rd would be closed "for some time".
A witness said it appeared one of the cars had hit another then rolled down the road, ending up on its roof.
Emergency services had to cut the roof off the car to get to the injured person, he said.
The road was closed and traffic backed up. Many drivers were trying to get to the airport.
"Some people have abandoned their rental cars and are now walking down to the airport."
Police said traffic management would be put in place but motorists were being asked to avoid the area if possible.
The Serious Crash Unit and police will investigate the circumstances of the crash.
