Fish and Game New Zealand is disgusted by reports South Canterbury farmers have been rigging the system to avoid irrigation restrictions.

Environment Canterbury is investigating allegations a truck load of men built a makeshift dam on the Pareora River next to a water level gauge.

Fish and Game CEO Bryce Johnson believes it was a deliberate attempt to fool the gauge into recording the river level was high enough for irrigation to continue.

"The water is a public resource, it belongs to all of us. It's a privilege for the rural sector for this sort of use, but abusing that is not on."

Bryce Johnson wants to see those responsible punished by ECAN.