The competing views were laid out in submissions to a government discussion document on how to reduce the emissions generated by industrial processes, and accelerate moves to alternatives.
Fonterra's director of global sustainability, Carolyn Mortland, said New Zealand's reputation must keep pace with global trends in emissions targets.
"We know that these energy-intensive processes like ours do contribute to New Zealand's emissions, and we need to support New Zealand to make that transition over time to renewable energy."
The organisation that represented the mining industry, Minerals West Coast, said at the moment, about 95 per cent of the boilers used by South Island food producers were coal-fired.
Helen Barnes of Horticulture New Zealand explained why.
"There's no natural gas in the South Island and biomass (wood chips) haven't been developed or proven to the point that growers have enough confidence to make the really large capital investments that are required to convert."
The Meat Industry Association, Horticulture NZ, Dairy NZ, and Westland Milk Products opposed putting a lid on coal too soon, but all were committed to emissions reductions targets.
The red meat sector was committed to becoming climate neutral by 2050, but spokesperson Paul Goldstone said the Government's climate change policy development needed to be eased in at a reasonable pace.
"You just can't pull the plug on coal-fired boilers right away, especially when meat exports are more critical than ever as part of New Zealand's Covid recovery."
Greenhouses need to be considered - Horticulture NZ
Horticulture New Zealand said in its submission that the consultation document did not appear to consider impacts of the proposals on greenhouse-grown crops.
It said phasing out existing coal boilers used for space heating of greenhouses would be "devastating" to indoor vegetable crop production.
Barnes said food production in New Zealand could be dramatically affected.
"If things move too fast we could end up seeing some of our members go out of business before they're able to implement new alternatives, which would mean you would be getting potentially more imports and less locally produced product, particularly in the South Island."
Westland Milk Products said the Government's plan was ambitious but came with risks, primarily the economic viability of communities on the West Coast which relied on a strong and viable milk processing industry.
It said careful planning was needed in order to acknowledge limited access to reliable alternative energy sources, and the coast's climate and geography that restricted options and would increase conversion costs.
Fonterra was aiming for net zero emissions in its manufacturing by 2050 and a 30 per cent reduction in emissions by 2030.
It said each factory was unique in what it did, the available energy sources and the age of assets. Ten of its 30 sites relied on coal as a primary source of energy; seven of which were in the South Island where there was no gas available, or feasible alternatives at the scale required.
Mortland said the company had already transitioned to new technology at a couple of its plants, including wood chip biomass at its Brightwater plant in Tasman, but the company was not trying to edge out others with its stance.
"What we're standing for here is that we don't think we should be compounding the problem by putting in essentially old technology, if you like - a coal boiler that will last 50 to 60 years when we know that during that time New Zealand has to transition to renewable energy."
Meat industry looking at new technologies
The meat industry uses about 80,000 tonnes of coal a year to heat boilers.
Its association said converting from coal to alternative fuels would be challenging and expensive, but it was looking at options, including new technologies such as heat pumps and biomass/firewood being installed into existing plants.
The association said constraints around electricity transmission would also need to be resolved, but it was pleased that the government plan to incentivise the accelerated uptake of new technologies through a proposed $70 million fund.
Paul Goldstone said the sector was also committed to becoming carbon neutral by 2050, and that would mean an estimated $80m spent on alternative heating systems.
"Government support to retire perfectly viable coal-fired boilers over to untested technology is going to be needed and we acknowledge the Government's support for that."
Barnes said the horticulture sector has been working with the Energy Efficiency and Conservation Authority to find a viable alternative.
"We're not quite there at the moment but we're going to continue working with EECA. We have been doing a bit of work ourselves around trying to get some good data on exactly what our growers are doing for their heating, and also what it would take - what they'd like to move to and what are the options they see ahead of them."
Labour pledged just prior to the election to accelerate electrification of the transport and industrial sectors and invest more in emerging technologies.
