Canterbury Regional Council says illegal clearing of land along the banks of the Lower Waitaki River is causing erosion and increasing the risk of severe flooding.
It says at least 20% of vegetation along a 65km stretch from Kurow to the river mouth has been cleared. The trees and vegetation act as a buffer zone between established river channels and exisiting farmland.
Council engineer Bruce Scarlett says the practice has accelerated in recent years with the dairy boom, as farmers cleared the buffer zone to create more pasture. He says what it really does is increase flooding and erosion for miles downstream.
Mr Scarlett describes the clearing as nothing more than a land grab by some farmers.