Two public servants were given just two days to assess and cost a two-year home insulation program for more than two million Australian households, an inquiry has heard.

They weren’t allowed to tell any colleagues or contact insulation stakeholders about their significant task.  The former Labor government’s Home Insulation Program, announced only weeks later, has been attributed to the deaths of four young men, one serious injury and hundreds of house fires.

Department of Environment assistant secretary Mary Wiley-Smith told the royal commission into the bungled program on Monday how she and another staffer worked long hours on the 2009 Australia Day long weekend to cost and assess the proposed scheme.

Ms Wiley-Smith said they received a call late Friday requesting costings for a two-year rollout that had to be approved by the finance department that Sunday.

“So you were asked to cost this over two days, not tell your colleagues and not contact industry?” Counsel Assisting Keith Wilson asked Ms Wiley-Smith.

“Correct,” she replied.

The pair didn’t have any assistance and had to examine potential risks, she added.

Ms Wiley-Smith said it was difficult to determine the impact of the scheme on the insulation industry given she was told not to contact any stakeholders that weekend.

She said issues around compliance in the industry were discussed, but she couldn’t recall whether any risks associated with physically installing insulation were raised.

Ms Wiley and her colleague ended up suggesting a five-year program with a staggered rollout utilising existing insulation companies.

This would have less of an impact on the insulation industry than a two-year rollout but still stimulate the economy, she said.

The $2.8 billion Home Insulation Program was announced in early 2009 to stimulate the economy, but was terminated in February 2010.

The royal commission before Ian Hanger QC continues.