Illustration: Ron Tandberg. Four young men died in workplace accidents while installing home insulation under the $2.5 billion scheme, which was launched as a stimulus measure at the height of the global financial crisis. There were also fires in hundreds of homes. Mr Fraser told Fairfax Media: ''If you are going to start the practice in which the new incoming government has royal commissions chasing its predecessor, then there'll be payback, and the next incoming government will do it, too - and you can ultimately make democracy as we know it, and understand it, unworkable.'' Mr Hawke said it was ''almost beyond belief that the government could contemplate doing anything which breaches what is now a more than century-old tradition here, which has been respected by governments and parties of both persuasions''. A spokesman for the Attorney-General would not confirm when, or if, cabinet documents had been handed to the commission, in which Ian Hanger, QC, will examine the process under which the flawed program was established and implemented.

It will also investigate if the deaths of the four could have been avoided ''if the Australian government had taken a different approach to identifying, assessing or managing workplace health and safety risk''. Senator Brandis insists the government respects the importance of cabinet confidentiality, but says in his letter it has decided the documents the Commonwealth will produce for the commission ''will include documents over which a claim for public interest immunity might be made, such as cabinet documents''. In providing such documents to the commission, he says the government will indicate that it does not waive its right to claim public interest immunity from their contents becoming public. ''Accordingly, should the commission wish to publish any of the cabinet documents … the Commonwealth requests that it be notified so that it can consider whether it is necessary to make submissions in relation to such documents or uses, or whether it should seek protective orders,'' he writes. Mr Dreyfus believes the government has already given cabinet documents to the commission, and says the action is at odds with the approach of every government since Federation.

''I am deeply concerned at the permanent damage this government's actions will do to the safeguards of good government in Australia,'' he said. University of NSW law professor George Williams said the move set an unfortunate precedent, ''not only in terms of a weakening of principle of cabinet confidentiality, but also of government's willingness to conduct inquiries into the actions of their predecessors''. ''Normally incoming governments accept that the people have exercised their judgment in throwing the old government out,'' he said. Loading Australian Catholic University vice-chancellor Professor Greg Craven urged the government to be cautious, saying: ''If you a start handing over documents too freely … then the other side is going to do the same thing to you.'' Prime Minister Tony Abbott has strongly denied the royal commission is an exercise in payback, saying: ''The whole point is to ensure we learn the right lessons from these terrible mistakes. It was probably the most disastrously conceived and executed Commonwealth government program in our history and I think it's important that we learn the right lessons from it, and that's what this royal commission is trying to do.''