SYDNEY — Australia has announced plans to create the world's largest network of marine parks to protect ocean life, with limits placed on fishing and oil and gas exploration off the coast.

The new reserves would cover 3.1 million square kilometres (1.9 million square miles), or more than one-third of Australian waters, taking in significant breeding and feeding grounds.

Thursday's announcement, after years of planning and consultation, came ahead of the Rio+20 Conference on Sustainable Development next week in Brazil, which Environment Minister Tony Burke and Prime Minister Julia Gillard will attend.

"It's time for the world to turn a corner on protection of our oceans," Burke said in the lead-up to the conference, which marks the 20th anniversary of the Earth Summit that declared the environment a priority.

"And Australia today is leading that next step." he added.

"This new network of marine reserves will help ensure that Australia's diverse marine environment, and the life it supports, remain healthy, productive and resilient for future generations."

The network will boost the number of reserves from 27 to 60, expanding protection of creatures such as the blue whale, green turtle, critically endangered populations of grey nurse sharks, and dugongs.

While some limits will be placed on energy companies, tracts of coast off Western Australia, where Shell and Woodside Petroleum recently won exploration permits, will still be open to oil and gas exploration.

Commercial fishing businesses will be hit hard, and are likely to receive millions of dollars in compensation.

"Over the coming months, the government will consult the fishing industry and fisheries management agencies on the design and implementation of a fisheries adjustment assistance package," said Burke.

While the Australian Conservation Foundation welcomed the initiative, calling it "a historic achievement", it was concerned that some areas remained under threat from the resources boom.

"Although the reserve network bans oil and gas exploration in the Coral Sea, the north west region has been left vulnerable to these threats," said chief executive Don Henry.

"We will continue to work with governments, the community and other stakeholders to improve protection for areas that have not got the protection they need."

A final consultation period of 60 days is not scheduled with the new reserves expected to be officially declared before the end of the year.