Pigs and cows are to be banned from entering all lakes, streams and rivers in Canterbury in a move to clean up waterways around the most intensive farms in the region.
Canterbury Regional Council has released new rules on stock access to waterways to come into effect in June 2012.
All stock are excluded from waterways under a natural resources regional plan if they cause adverse effects, including pugging of banks, discolouration of water and increased bacterial levels.
But intensively farmed stock, which the council names as pigs and dairy cattle, will be completely prohibited from waterways.
Commissioner Tom Lambie says lower-intensity farmers, such as sheep and cropping farmers could also be affected by the tighter rules at certain times of the year.
"You may increase the intensity on your particular land at a potential time and therefore it's important that you're actually complying with the rules as well.
"It's the level of intensity rather than the location that's the most important thing here in protecting our waterways."
Stock access to waterways near bathing sites and within 1km of a community drinking water supply is also restricted under the new rules.