Farmers in the Waikato must build tunnels under country roads to move their stock rather than let them foul the roads.
The Waikato District Council has decided to act after numerous complaints from motorists about the mess and smell left by herds crossing roads from one part of a farmto another.
Council roading services group manager Kaye Clark said encouraging farmers to build underpasses - which cost on average $80,000 - would save country roads and motorists' noses in the region.
Mrs Clark said cow dung on the roads created an environmental hazard and motorists were growing intolerant of the mess left on their cars.
She said there was an increasing number of lifestyle enthusiasts moving into the district, living on small blocks and working in the city.
"If you're going into work in the city and you turn up at a meeting or work and your car smells of effluent, there's less tolerance for that," Mrs Clark said.
The ban on stock movements across roads will come into effect by 2015.
Mrs Clark said the council would be looking at the subsidy given to farmers for building underpasses as part of the plan.
But Federated Farmers Waikato regional president Peter Buckley said farmers were not happy with the council reviewing the stock-crossing bylaw.
He said underpasses should be built for safety reasons, but some farmers had stock crossings on dead-end roads which only saw one or two cars a day.
"If they want underpasses because it's a social issue, there should be more [money] from the council."
The council plans to review the stock-crossing bylaw in parts, phasing out permits for stock crossings by a date to be confirmed and requiring farmers to have underpasses by December 31, 2015.
