Sixty firms that contribute almost half of New Zealand's greenhouse gas emissions are pledging to help the country reach its net zero emissions target by 2050.

The businesses' chief executives have formed the Climate Leaders Coalition after talks with the Sustainable Business Council. The group includes leaders of Z, Westpac, Ngai Tahu Holdings, Vector, Air New Zealand, Spark and NZ Post.

By signing the CEO Climate Change Statement, each of the business leaders has committed to measuring and reporting their greenhouse gas emissions and working with suppliers to reduce emissions, with the aim of helping to keep global warming within two degrees, as specified in the Paris Agreement.

The businesses will individually set targets to reduce emissions and report on progress annually. Most businesses involved in the coalition are already reporting their targets to reduce emissions.

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But Z Energy chief executive Mike Bennetts, leading the collective commitment, said it would be up to consumers, media and the general public to hold each business involved in the coalition accountable for every emission reduction report put out. The coalition will not publish a central report, he said.

"When it comes to emissions, customers want to know what the businesses they are shopping at are doing. It will come down to individual customers and their connection with these individual companies," Bennetts said.

SUPPLIED Fonterra chief operation officer for global operations Robert Spurway says the coalition was a step in the right direction.

Z Energy has committed to reducing its emissions by 30 per cent by 2020 for its internal operations.

Bennetts said Z Energy sold 9.3 million tonnes of carbon to its customers but was also looking to reduce New Zealanders' reliance on fossil fuels.

"Sounds weird because we're incentivising people to buy less of our products, but that's what these public commitments enable us to do."

123RF Sixty Kiwi businesses are responsible for about half the country's emissions.

Fonterra chief operation officer for global operations Robert Spurway said the company had also pledged to 30 per cent reduction, but by 2030 from a 2015 baseline.

"At the moment there is no legal requirement for businesses to complete emission reporting. The Government is looking at this over time, as part of New Zealand's commitment to climate change, but this accelerates that," Spurway said.

"It gives businesses that opportunity to lead through commitment by all those businesses within the coalition to report on an annual basis. It's a step in the right direction."

Professor James Renwick, of the Victoria University school of geography, environment and earth sciences, said it was good news for climate change action in New Zealand.

"This coalition, comprising almost half of the country's greenhouse gas emissions and including some very prominent businesses such as Fonterra and Air New Zealand, has the potential to make a significant difference. We will have to wait and see what actions the members of the CLC actually take, but the stated aim of reducing emissions to meet Paris Agreement limits is excellent," he said. "The CLC group is responsible for a sizeable fraction of the country's emissions of carbon dioxide, from transport, energy production, and industrial use of fossil fuels. These are the sectors where emissions growth has been fastest in the past two decades, so it's exciting to see businesses tacking emissions in this area."

PHIL JOHNSON/STUFF CIRCUIT Z Energy chief executive Mike Bennetts says it is up to the general public to keep track of the dozens of businesses' progress.

Renwick said, to combat climate change, a new industrial revolution was needed, switching business and society to energy sources that would not affect the climate. "Failure to step up will indeed put our competitiveness at risk, and ultimately would seriously damage the livelihoods of millions or people around the world. This is an opportunity for New Zealand to show the world how to make the transition to a zero-carbon future."

Professor Tim Naish, a climate scientist at the Antarctic Research Centre said it was significant that the aviation, dairy and petroleum sectors were signatories.

"But just as it applies to governments that pledged in Paris, good intentions must translate into action, and time is short."Agreeing to measure and report their emissions is a strong move. It is important they commit to ambitious targets in the first five years. The science shows us that collectively if we leave it much longer this will require negative emissions and a technological solution."