Peter Garrett says he was never briefed on fatalities while visiting a NZ insulation scheme because he was in the country to speak about whaling.

Former environment minister Peter Garrett has accepted “ultimate responsibility” for Labor’s botched home insulation program but insists others should share the blame.

Four installers lost their lives under the Rudd government scheme in 2009 and 2010, and Mr Garrett told a royal commission on Tuesday that, although he visited a similar New Zealand scheme in 2007, he hadn’t been briefed on fatalities there because his priority had been to speak about whaling.

The commission is investigating what advice Labor received and whether the deaths of Matthew Fuller, Rueben Barnes, Mitchell Sweeney and Marcus Wilson could have been avoided.

Mr Sweeney’s brother, Justin, said Mr Garrett should have halted the program after the first death.

“One death is enough, not four,” he said outside the Brisbane Magistrates Court.

The program was terminated on February 19, 2010.

In his statement to the inquiry, Mr Garrett said he was ultimately responsible for the scheme, although then senator Mark Arbib oversaw elements of the government’s $42 billion stimulus package.

Mr Arbib has already told the inquiry his sole responsibility was to sell the program, while former prime minister Kevin Rudd is expected to defend his role on Wednesday afternoon.

“I was responsible for the rollout of the HIP (home insulation program) and bore ultimate responsibility for its implementation,” Mr Garrett wrote.

But under cross-examination by counsel assisting Keith Wilson, Mr Garrett said everyone involved had responsibility to minimise risks.

“We share responsibilities with those other institutions that equally have them, such as state regulatory bodies, employers, ultimately employees as well.”

Mr Garrett said risk was reduced through various measures, including a national register of installers and audit and compliance guidelines.

He said that while he acted on all safety advice he received, his trust in that advice waned after Mr Fuller became the first person to die under the scheme.

“Over time, I interrogated the advice more thoroughly and I did reach a point where I wasn’t trustful of all of the advice that I received,” he said.

Mr Fuller was electrocuted when he put a metal staple through an electrical cable while installing foil insulation on October 14, 2009.

Mr Garrett said he didn’t immediately ban foil because he wanted to understand the full circumstances surrounding Mr Fuller’s death, given the divergent views in the industry about the product.

He banned metal staples from the program on November 2, 2009.

Foil wasn’t banned until February 9, 2010, five days after Mr Sweeney’s death.

Mr Sweeney was also using metal staples to secure foil insulation when he was killed.

It was the same practice linked to the deaths of three New Zealand installers in 2007.

But Mr Garrett says he only became fully aware of those deaths “very recently”.

“Actually, not until such time as the commission started examining this matter (in mid-March),” he said.

Mr Garrett said the New Zealand electrocutions were only briefly raised after Mr Fuller’s death, but added he should have been told earlier.

Mr Garrett will resume his evidence on Wednesday.