BHP has said it will not support the Minerals Council’s bid to strip environmental groups of their ability to advocate for policy change.

The surprising move comes amid increasing pressure on Australia’s biggest miner to distance itself from the Minerals Council, which has taken a hardline position against any form of credible action on climate change. The government will soon table a bill aimed at limiting the ability of any charity to use donations raised from overseas on advocacy in Australia.

The Minerals Council has argued that environmental charities should be forced to commit 90% of their resources to on-the-ground environmental remediation, education and research, leaving only 10% for political advocacy.

It made the suggestion in a submission to a Treasury inquiry that asked stakeholders to comment on a suggestion that green groups be required to devote half their resources to on-the-ground remediation.

Since then BHP has faced a shareholder resolution at its London AGM, calling on the company to leave the MCA and arguing the council’s climate policy “is fundamentally at odds with our company’s long-term financial and strategic interests”.

It said BHP risked reputational damage by being a member of bodies that “hold policy and advocacy positions out of step with community expectations”.

The resolution, put by 100 Australian shareholders through the Australasian Centre for Corporate Responsibility, was supported by the Californian state employees pension fund, Calpers. Representatives from HSBC bank and the Church of England also voiced support.

The outcome of the vote will not be known until after the Australian AGM next week.

As news of the resolution came to light, BHP appeared to act preemptively, agreeing to review its membership of the MCA, and announcing that before the end of the year it would release a “list of the material differences between the positions we hold on climate and energy policy, and the advocacy positions on climate and energy policy taken by industry associations to which we belong”.

The Guardian understands BHP has now written to a number of environmental groups, including the Australian Conservation Foundation, saying it does not support limits on the ability of environmental groups to engage in advocacy. The letter is understood to outline how the company’s positions on a number of climate and energy policy questions differ from those of the MCA.

The executive director of the ACCR, Brynn O’Brien, said BHP’s move was not enough.

“The MCA has been a toxic drag on Australian public debate and democracy,” O’Brien said. “BHP continues to spend shareholder funds on membership of the MCA. Until BHP withdraws from the MCA, it should expect to be held to account for bankrolling the MCA’s activities.”

BHP and the Minerals Council of Australia declined to comment.