The Accident Compensation Corporation (ACC) has helped to bankroll a mining project on conservation land which some fear could put one of the world's rarest frogs at risk.
Just 2000 - 5000 Archey's frogs are left in the world - and they have only two known habitats, in Coromandel and near Waitomo.
ACC has invested $2 million of taxpayers' money in Waihi-based company Antipodes, which has a permit to explore the Coromandel forest for gold.
ACC's investment, which is now worth just $50,000 because of falling gold prices, has been criticised by the Green Party for breaching United Nations' responsible investment guidelines, of which ACC is a signatory.
They stipulate that ethical issues and the environment should be considered in investments.
ACC investment manager Nicholas Bagnall said the organisation treated the UN guidelines as a framework rather than rules.
He said the corporation had its own ethical policy, which was to avoid investing in anything which would be deemed unethical by most New Zealanders.
To determine that it looked at New Zealand legislation, and worked on the principle something would be illegal if most New Zealanders deemed it unethical.
When asked if ACC had done due diligence on the company, Mr Bagnall said that it had only seen information about the project that was public. He said that with all investments, it tried to do analysis - but that it might not necessarily be described as due diligence.
Green Party mining spokesperson Catherine Delahunty said ACC should withdraw its investment.
She said the corporation had shown a lack of regard for the species, by chasing a quick buck, and that ACC's comments showed it was financially inept.
An Antipodes spokesperson said mining was still a long way off and it hoped to start looking for gold in a couple of years. In the meantime, it was trying to find money to bankroll the project.
Its mining partner, Newmont Waihi, had done surveys on where the Archey's frogs' habitats are. It says those surveys will mean they won't erect rigs in precious habitats.