The Australian government has ordered a safety audit of every house that was fitted with foil insulation as part of a nationwide energy-saving plan.
Environment minister Peter Garrett suspended the programme on Tuesday after it was linked to the deaths of four insulation installers.
The ABC reports that he was warned last year of safety concerns within the scheme.
The Coalition says Mr Garrett should resign after several electrocution were linked to the program, but he has rejected the calls.
He was grilled in Parliament on Wednesday over whether he did enough to heed industry concern about how some contractors were installing the insulation, which has now been rolled out to almost 40,000 houses.
In response to questions from the Opposition, Mr Garrett confirmed he was contacted last year by the National Electrical and Communications Association about the safety problems in the scheme.
Opposition Leader Tony Abbott said Mr Garrett's actions had been "utterly incompetent".
The Government will foot the bill for all the inspections but Mr Garrett was unable to say what that might cost.