Police are investigating two separate crashes which occurred on the Huon Highway in southern Tasmania this morning.

About 5am a white 2002 Nissan Pulsar travelling in a southerly direction collided with the side of a white 2002 Kenworth truck at Port Huon.

The truck, which was towing a trailer loaded with logs, was exiting a gravel car park opposite the Kermandie Hotel at the time of the crash.

The 68 year old man driving the car was initially trapped in the vehicle.

After being freed by State Emergency Service volunteers he was taken to hospital with serious injuries.

The 36 year old man driving the truck was not physically injured.

Initial investigations indicate that inattention and excessive speed may have been contributing factors in the crash.

The second crash occurred about 8.15am when a silver 2010 Toyota Camry travelling in a northerly direction left the road and collided with a power pole at Franklin.

After colliding with the pole the vehicle rolled several times, bringing down powerlines before coming to rest in a paddock.

The 74 year old man driving the car was airlifted to hospital. His injuries are not believed to be life threatening at this stage.

Investigations into the cause of the crash are continuing, however it is possible a medical episode occurred.

Traffic was reduced to one lane at both scenes whilst investigations were undertaken and power restored at the Franklin crash.

Crash investigators are urging anyone who witnessed either crash, or may have dash cam footage of either vehicle prior to the crash, to come forward.

Information can be provided by calling Tasmania Police on 131 444 or anonymously through Crime Stoppers on 1800 333 000 or online at crimestopperstas.com.au/