A person trapped after hitting a tree in Auckland's New Lynn has been left with serious injuries.

A Northern Fire Communications spokesman said two fire crews were in attendance at the crash on Clark St, and were extracating one person from the car.

"They're lightly trapped... It basically means they're not seriously trapped or crushed."

He said they received the call to the accident at 4.37pm.

A police spokeswoman said the two eastbound lanes were blocked, but traffic was apparently flowing.

The person trapped had been transported to Auckland Hospital in a serious condition, a St John spokesman said.