UPDATE: THE driver involved in this afternoon's truck roll-over has been hospitalised with a serious leg injury.
The 30-year-old was freed from the cabin by a Coffs Harbour State Emergency Service crew after two hours.
The ambulance media unit said the man was conveyed to Coffs Harbour Base Hospital in a stable condition.
Police are investigating what caused the water tanker to leave the highway.
1.48PM: EMERGENCY services are on the scene of a truck roll-over on the Pacific Highway north of Coffs Harbour.
The driver, a male aged in his 30s, remains trapped in the cabin, but police and paramedics have confirmed he is conscious and breathing.
The heavy vehicle rolled onto its side in bushland off the southbound lane near Novotel Pacific Bay just after 1.30pm.
One lane of the highway has been blocked off to allow emergency services to free the driver.
Roads and Maritime Services have advised the salvage operation is likely to occur tonight.
Motorists are urged to exercise caution in the area.