A New Zealand fresh water scientist believes regulation is the only way to protect waterways from the effects of dairy farming.
Mike Joy, of Massey University, says the quality and ecology of New Zealand's rivers, streams and lakes are continuing to decline.
Dr Joy says the Clean Streams Accord, formed as a partnership between the dairy industry, local government and central government, has been ineffectual in minimising the impact of dairying.
He believes they only way that is going to change is if there are robust rules in place.
