Last week the father of a former Griffith man killed in the scheme gave heartbreaking evidence when he took to the witness box.

Griffith’s Martin Sweeney, who lost his son Mitchell, told the inquiry no family should have to endure what his did.

On Friday Greg Combet fronted the royal commission and fought back tears in reflecting on the deaths of four young men.

The former climate change minister, responsible for the $2.5 billion scheme in its final days, expressed horror at the “unscrupulous people” milking the ceiling batts rollout and conceded the entire program was “fundamentally flawed” from the outset.

The Abbott government has insisted the royal commission was about learning the lessons of workplace safety.

Grieving families welcomed a final, exhaustive investigation.

But the Opposition believes the process was just as much a “political witch-hunt” as anything else.

“This was supposed to distract from what they were doing in budget week,” a senior Labor source said.

“There was a clear political ploy to drag this stuff out to remind people how much they disliked the last government, but people seem to have moved on. People are more interested in what the government is doing.”