New Zealand unveils plans to tax the greenhouse gas emissions from farm animals, in a controversial proposal designed to tackle climate change.

Prime Minister Jacinda Ardern said the levy would be the first of its kind in the world.

New Zealand’s 6.2 million cows are among the country’s biggest environmental problems.

The scheme would see farmers pay for gas emissions from their animals, such as methane gas in the farts and burps from cows, and nitrous oxide in the urine of livestock.

Ardern told farmers they should be able to recoup the cost by charging more for climate-friendly products.

She said the “pragmatic proposal” would reduce agricultural emissions while making produce more sustainable by enhancing New Zealand’s “export brand”.

The proposal could cost Ardern rural votes in next elections as farmers condemned the plan.

Andrew Hoggard, president of the Federated Farmers lobby group, said the scheme would “rip the guts out of small-town New Zealand”.

He argued the tax could push farmers into growing trees on fields currently used to rear livestock.

The government hopes to sign off the proposal by next year and the tax could be introduced in just three years’ time.