Australian taxpayers will lend $US100 million ($110 million) to a mining joint venture run by BHP Billiton and Rio Tinto in Chile, under the latest funding deal by Australia's controversial Export Finance and Insurance Corporation.

The loan to two of Australia's largest and most profitable companies is being made despite recent criticism of EFIC by the Productivity Commission. It advised the corporation to focus more on small exporters who were unable to secure finance rather than wealthy multinationals.

Major players: The miners operate the Escondida copper mine in Chile. Credit:Reuters

It also comes at a sensitive time for the Abbott government, which has denied financial assistance to companies such as Alcoa and Holden, amid its campaign to ''end the age of entitlement''.

Under the terms of the latest loan, the $US100 million will be lent to a holding company called Minera Escondida Limitada, which is 57.5 per cent owned by BHP and 30 per cent owned by Rio. Japanese companies Mitsubishi and Nippon Mining own the rest.