Southland Regional Council says stock trucks leaking effluent onto roads should be made a specific offence under the Land Transport Act.
Chair Ali Timms says that if a truck is found discharging effluent where it could reach water, a $750 fine can be issued by council staff.
But, she says, the council has not been able to act in most of the cases in the last couple of weeks.
Ms Timms says it's disappointing that many farmers apparently chose to ignore the advice of Dairy NZ to stand their stock off green feed before transport.
The council intends to ask Bill English MP to initiate a law change.
