The Federal Government says it will make confidential Cabinet documents from the former Labor government available to a royal commission into the home insulation scheme.

Four young insulation workers died while working on the rollout of the home insulation scheme set up by the Rudd government in 2009.

The commission is investigating if the deaths could have been avoided and is looking into whether the government sought the appropriate safety advice.

Attorney-General George Brandis has written to the Opposition saying Cabinet documents may be used as part of the process.

He says if the royal commission decides to use Cabinet documents, it should let the Commonwealth know so it can decide if it should seek protective orders.

Prime Minister Tony Abbott says it will help the inquiry find out what went wrong.

"Royal commissioners have very extensive powers to demand documents, to summon and question witnesses. This is a very powerful inquiry and it should do its job," he said.

But shadow attorney-general Mark Dreyfus has attacked the decision to release the documents, saying it undermines the long-standing principle of Cabinet confidentiality.

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"The damage is now done because it means that every future Cabinet meeting will not be secure," he said.

"In every future Cabinet meeting, ministers will be looking over their shoulders, will be thinking 'perhaps what I say here will become public'."

The ABC has asked Senator Brandis for comment, but has had no response.

Under the multi-billion dollar Rudd government stimulus package, insulation was installed in nearly 1.2 million homes, but problems soon emerged.

Matthew Fuller, Rueben Barnes, Mitchell Sweeney and Marcus Wilson died and government figures show there were 224 fires linked to the program.

Document release would discourage future debate: Fraser

Former prime minister Malcolm Fraser has expressed alarm at Senator Brandis' decision.

"It discourages debate in Cabinet, free and open debate, which it is meant to be - which is why there's a time limit on when documents are published and when they are not," Mr Fraser said.

"And also it invites payback from a new government, when there's another change of government sometime in the future, and that kind of practice would ultimately do great damage to Australian democracy."

There have already been numerous investigations into the problems with the Rudd government's home insulation program, including a senate inquiry in 2010, a performance review by the National Audit Office, a coroner's inquest in both NSW and Queensland, a scientific study by the CSIRO and two other reviews or reports.

Mr Fraser says that because of these investigations, using recent cabinet documents is not in the public interest.

"What's it going to find? Is it going to find that certain ministers ought to be prosecuted?" Mr Fraser said.

"That's most unlikely; there have already been coronial inquiries. I think the public know that the program was very incompetently managed.

"I'm not aware of it happening in Australia's history, I'm not aware of it happening in British history.

"Many of our practices obviously flow from British experience."

Mr Fraser says that should this happen now, it would be much more likely to happen again in the future, until there are "sensible people operating" in the Parliament.

