Concern a renewed consent for a Canterbury irrigation scheme will reverse climate change efforts

The region's Mayfield/Hinds/Valetta irrigation scheme is seeking a 10-year replacement consent on more than 56-thousand hectares of farmland.

But the move's angered environmental groups, who allege the practise will leech nitrates into drinking water, at a rate 25 times above safe levels.

Freshwater advocate Angus Robson says the high-polluting consent gives the green light for intensive dairy farming to continue.

He says the two often go together and it'll lead to soaring greenhouse gas emissions - a step backwards from our efforts to reduce climate change.

A public meeting's been called at Christchurch's Burnside High School on Wednesday to shed light on the potential impacts.