The federal government has rejected calls to rethink its defence of coal after Australia's biggest producer capped output to reduce greenhouse gas emissions, in a victory for the anti-coal lobby.

Switzerland-based Glencore, which is also one of the world's biggest miners, made the surprise decision after being lobbied by a powerful anti-coal group that includes Australian retail superannuation funds.

"We believe this transition is a key part of the global response to the increasing risks posed by climate change," the company said in a statement on Thursday night.

But federal Resources Minister Matt Canavan believes Glencore's decision is more about protecting its market share than protecting the planet.

Glencore says it took the decision after talks with the investor-led group Climate Action 100+, which was formed to lobby companies to take action against climate change.

"As one of the world's largest diversified mining companies, we have a key role in enabling the transition to a low-carbon economy," it said.

Glencore noted "the increasing risks posed by climate change" and explicitly referenced the 2015 Paris climate accord, which set a target of keeping global warming well below 2C by the end of the century compared with pre-industrial levels.

But Senator Canavan said Glencore last year made one of the biggest purchases of coal mines in the world's history.

"Call me cynical, but I think their announcement overnight appears to be much more to do with the self-interest of Glencore than the planetary interest of trying to save the climate," he told reporters in Canberra on Friday.

While international investors might disagree, but there were "plenty of people wanting to fund coal mines".

"They're often obviously not the traditional houses that seem lock-step into some kind of Atlantic alliance against coal-fired power, but in our region, hundreds of coal-fired power stations are being built," the senator said.

Climate Action 100+, which has 300 investor members with $US32 trillion of assets under management, plans to use Glencore as "an example of how low carbon transition strategies can be achieved" in the mining sector.

Steering committee member Emma Herd, from the Australia-based Investor Group on Climate Change, said investors were taking action around the world as part of growing concerns about systemic climate change risks and the likely impacts on investment returns.

Greenpeace Australia Pacific's Jonathan Moylan said the coalition government was increasingly isolated on coal and demanded Senator Canavan explain how it was planning for a future beyond coal.

Glencore will limit its annual coal production capacity "broadly to current levels" and prioritise investment in commodities supporting low emissions technology.

This means its global coal output this year will be 145 million metric tonnes, in line with the previous year.