Under the proposals, the existing Macquarie Island Marine Park will be tripled in size, bringing a total of 475,465 square kilometres (183,578 square miles) under protection.

That is an area roughly the size of Spain or Cameroon and much larger than Vietnam or Japan.

The protections mean the area will be "completely closed to fishing, mining and other extractive activities", according to Australia's Minister of Environment Tanya Plibersek.

Existing fishery operations targeting the Patagonian toothfish will be allowed to continue.

Macquarie Island sits halfway between Australia and Antarctica and is home to royal penguins, fur seals and a subantarctic science hub.

"Macquarie Island is an exceptional place. It's a remote wildlife wonderland - a critical breeding ground for millions of seabirds, seals and penguins," said Plibersek.

Environmental groups have backed the plan, fearing the area could be targeted for seabed mining and unsustainable commercial fishing.