Kevin Rudd was personally warned of "unacceptably high" safety risks in his government's roof insulation scheme before three installers died.
The government on Thursday released letters between then environment minister Peter Garrett and the prime minister.
On two separate occasions last year - October 28 and 30 - Mr Garrett warned Mr Rudd of "unacceptably high occupational health and safety risks".
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Despite the warning, the scheme continued.
Two workers died fitting insulation in November, and another in February.
The $2.45 billion scheme was then axed.
Another installer had died before the warnings were sent to Mr Rudd, taking the total deaths to four.
While Mr Garrett was demoted over the scheme's failings, the opposition has sought to spread the blame to Mr Rudd and other ministers.
The letters show Mr Rudd was kept updated on the scheme's rollout and problems.
In one October letter, he asked that Mr Garrett "continue to consult my department closely".
But while Mr Rudd and Mr Garrett were clearly aware of safety problems, it appears to have been left largely to the minister to try to make the scheme safer.
The letters show the two men were preoccupied with reducing the size of the government rebate for roof insulation.
The federal government says it won't release the entire paper trail of letters that warned the prime minister.
