A bureaucratic error has rendered eight years' worth of approvals for oil and gas operations in sensitive marine areas invalid, Resources Minister Josh Frydenberg has revealed, forcing the government and Labor to rush through laws to make the projects legal.
Conservationists say it means the projects did not have the correct environmental approvals, raising questions over whether the effect of mining operations on ocean areas of high conservation value were properly considered.
In a statement on Wednesday, Mr Frydenberg said his department had advised that a number of offshore petroleum titles had been "subject to incorrect renewal and extension processing". This was the result of departmental administrative error between 2008 and 2015.
The error relates to projects with so-called "prior usage rights", which allowed them to keep operating when a protected marine reserve was established around them.
Fairfax Media understands that any subsequent renewals or extensions in the marine reserves should have been referred to the Environment Minister for approval, but were not.
Some 42 renewals or extensions are believed to be affected. Initial approvals had been properly granted.
Mr Frydenberg said the government would urgently pass laws through Parliament "to resolve this issue".
"Following consultation with the Opposition, this will proceed with bipartisan support," he said.
"The legislation will retrospectively deem the relevant renewal and extension decisions to have been correctly processed, enabling titleholders to continue their operations as per usual."
He said all mining operations continue to be subject to Australia's "stringent" environmental, safety and integrity regime administered by an independent regulator.
Administrative processes have been established to ensure the error is not repeated.
Save Our Marine Life campaign manager Michelle Grady said it was "very concerning that oil and gas operations have not had the correct environmental approvals" for operating in vulnerable marine areas.
"Mining in marine parks is a concession, which must have the highest scrutiny given the impact on marine life, fishing and local communities that can occur as a result of seismic exploration, drilling operations and oil spills," she said.
The government is reviewing Australia's marine park network, and conservationists fear it will fail to curtail the oil and gas industry, which is pushing for better access to Australia's seabeds.
There are also concerns it will allow commercial fishing in sensitive coral reefs and pristine waters.
The government controversially allowed petroleum exploration in areas identified as marine sanctuaries while the review was under way.
Ms Grady said the string of decisions meant it was "critical going forward that marine parks are given a much higher priority in decision making by the resources portfolio in future".
Greens senator Rachel Siewert said the invalid oil leases showed "a disregard [for] environmental issues when it comes to the petroleum industry".
"This opens up a can of worms on all leases over marine protected areas. Have other mistakes been made in the environmental approval process of other leases in marine parks?" she said.
"It is concerning that it wasn't even considered that these leases would need environmental approval."
Senator Siewert said it was disappointing that Labor was "siding with the Government to shove through legislation that fixes this administrative loophole" and pledged to refer the matter to a Senate committee for inquiry.
The Australian Petroleum Production and Exploration Association said it supported the introduction of new legislation to address "an administrative oversight that has had no impact on the environmental obligation on titleholders".
"A petroleum title does not constitute an environmental approval," a spokesman said, adding titleholders would still need to apply for separate environmental and safety approvals for all regulated activities.