There have been estimates it may cost as much as $50 million.

"It certainly will be quite expensive, there's no doubt about that," Treasurer Wayne Swan told ABC Radio today when asked whether the cost would run into the tens of millions.

The Government yesterday announced the foil insulation would be ripped out or homes would be retro-fitted with safety switches.

Mr Swan said it was impossible to accurately determine the full cost of the measure yet because it would take some time to carry out roof inspections.

"We will account for this as soon as we practicably can."

Mr Swan warned that the additional cost could impact on other government programs.

"We will certainly have to make our budget fit these costings.

"It could well be the case that we will have to make adjustments elsewhere in the budget."