If Southland local authorities fail to, the Government must restrict cattle numbers in the Waituna Lagoon catchment to save it from dairying pollution, Green Party co-leader Russel Norman says.
A recent Environment Southland monitoring report said the lagoon was under threat from high levels of nitrogen and phosphorous, as a result of dairy farm runoff.
Southland Conservation Board last week said the next heavy rain could have dire consequences.
"Immediate government intervention is required if we are to save this magnificent internationally protected lagoon and wetland," Dr Norman said.
Dairy farmers had not broken rules by having cows in the catchment.
"The regional council has failed in the past to put in place rules to limit the number of cows and now central government needs to step up to the plate to help clean up the mess. It has an international obligation to protect the lagoon and has ample powers to intervene," Dr Norman said.
"Nick Smith needs to make it clear to the regional council and the dairy industry that central government will reduce stock numbers if they don't sort it out themselves within the week."
Warnings the lagoon could turn irreversibly septic have so concerned Ngai Tahu it is bringing iwi elder Sir Tipene O'Regan to talk to Environment Minister Nick Smith, when he was due to visit today.
Dr Smith was to visit the lagoon -- part of the internationally recognised Awarua wetlands southeast of Invercargill -- to be briefed on issues caused by intensive dairy farming run-off.
He was due to meet concerned parties and local runanga representatives, including Sir Tipene, the traditional head of the Awarua subtribe.
Research by the regional authority estimated an extra $1.99 million was needed in the next financial year to continue to stop the lagoon from "flipping".
