The 33-year-old and the police officer were both taken to Ballarat Base Hospital following the crash, which happened about 10.30am. 

"A vehicle has rammed a police car, that's all come about after a pursuit earlier," said Acting Senior Sergeant Paul Martin. 

"After the pursuit was terminated, the vehicle continued towards the township of Ballarat, performed a U-turn, drove a distance, performed a second u-turn and drove into oncoming traffic and has collided with a police vehicle." 

The unmarked police car had been pushed back 30m from the collision site towards Ballarat. 

Police would not comment on the nature of the incident in Geelong, but said the man would be formally interviewed once he was in a fit state. 

Acting Senior Sergeant Martin said three or four units were involved in the pursuit, including the unmarked car involved in the crash. 

It is believed it was called off because of the speed reached by the man in the Mercedes C-class he was driving. 

His German shepherd was also in the car, but was not injured in the crash.