A man has remained trapped for hours following a truck rollover west of Cessnock which spilt 20,000 litres of rancid fish product into a creek bed.

Around 25 emergency service personnel have been on the scene trying to free the man from the vehicle.

“Approximately 9am a truck has rolled over on Putty Road at Putty. The driver was trapped in the cabin of the truck,” Acting Superintendent Brad Brian said.

The man is expected to be flown to John Hunter Hospital and police are investigating the cause of the crash.

The man, believed to be in his 50s, was carrying fish product including fish guts and heads.

“There’s approximately 20,000 litres of fish product the truck driver was carrying which was spilt into the dry creek bed,” Acting Superintendent Brian said.

Emergency services are awaiting the Environment Protection Authority NSW and local council to arrive on scene to investigate the spill.

They are also organising a trucking company to clean up the spill, which is expected to take place tomorrow.

“It’s not causing any damage at the moment, given the fact the creek bed is dry so it’s not moving or running anyway,” Acting Superintendent Brian said.