On the Friday afternoon of the 2009 Australia Day weekend, federal Environment Department bureaucrat Mary Wiley-Smith and a fellow bureaucrat were told to have the plan ready for costing by the Department of Finance on the following Monday.

The revelations came in the first day of hearings in Brisbane at the royal commission the Coalition government set up in December with the task of finding whether the Labor government had received advice, warnings or recommendations about the program.

The scheme was established in 2009 by then prime minister Kevin Rudd and environment minister Peter Garrett to boost the economy during the global financial crisis. It involved rebates paid to home owners or installers of roof insulation. Four installers died and badly installed insulation caused hundreds of house fires. Mr Rudd and Mr Garrett have been called to give evidence at the inquiry into the $2.5 billion program.

Ms Wiley-Smith, an assistant secretary in the resources and energy efficiency division, confirmed she and her colleague were told to keep the matter confidential and they could not ring industry representatives to seek advice; however, an industry representative who had been in touch with a minister's office was allowed to contact them.

Under questioning from Richard Perry, SC, representing one of the families of the deceased, Ms Wiley-Smith acknowledged the directive to keep the matter confidential had not occurred before.

She also acknowledged she had heard talk among the Environment Department's communications staff and the risk assessment staff by July 2009 about deaths in a New Zealand insulation program.