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.

The bureaucratic error has rendered 42 approvals for oil and gas operations in sensitive marine areas invalid. Credit:James Davies

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.