US aluminium company Alcoa will pay A$55 million ($38.9 million) to remediate native forest it illegally cleared in Western Australia in order to mine bauxite, Australia's environment ministry said on Wednesday.

The payment relates to nearly 2,100 hectares (5,190 acres) of land cleared between 2019 and 2025 in the Northern Jarrah Forest, south of Perth, without seeking government approvals.

The ministry called the payment "unprecedented" as the largest of its kind, and said it will fund conservation-focused initiatives including ecological offsets, programmes to preserve endangered black cockatoos that nest in the jarrah trees, and improving the management of invasive species.

Alcoa said it operated in accordance with Australia's laws while agreeing to the payment to acknowledge its historical clearing.

The company has mined bauxite, the raw material for aluminium, in Western Australia since the 1960s and has cleared around 28,000 hectares (69,000 acres) of the state's native jarrah forest. Of the around 5,500 people Alcoa employs nationwide, some 4,300 are in the state.

Opposition to Alcoa's land clearing and environmental impact on the world's only jarrah forests has been growing, with a recent proposal to clear a further 11,500 hectares attracting a record 59,000 submissions from the public to the state's environment watchdog.

The government is undertaking a strategic assessment to gauge the cumulative environmental impact of Alcoa's current and potential future mining operations through to 2045, the environment ministry said.

Alcoa would be allowed to continue clearing "limited land" for 18 months under a national interest exemption to ensure the continued supply of bauxite while the assessment is being completed, it added.

Alcoa has pledged a further A$4.2 million in offsets for activities covered by the exemption.

"We are committed to responsible operations and welcome this important step in transitioning our approvals to a contemporary assessment process that provides increased certainty for our operations and our people into the future," Alcoa CEO William Oplinger said in a statement.