A main road in Tauranga is backed up with traffic following a crash.

Emergency services were called to the scene of a two car crash on Cambridge Road, just before 4pm.

A caller to the 0800 SUNLIVE news hotline says police and ambulance have gone racing past.

"I have just driven through and it looks like a head on collision."

A police spokesperson says one lane is blocked.

"There is a large build-up of traffic in both directions.

"One person is reported to have serious injuries and one person is moderately injured.

"Emergency personnel at the scene are assisting with traffic control."