The royal commission into the controversial robodebt scheme will focus on the people in charge, promising to hold senior government figures to account.

Hundreds of thousands of people were caught in the Centrelink debacle and the investigation is examining what went so badly wrong.

The commissioner and senior counsel assisting made brief opening statements in Brisbane on Tuesday morning but no witnesses were called.

That won’t occur until October when the first two-week public hearing takes place, examining a number of issues including at what point the unlawful debt recovery scheme became automated.

Kicking off in 2015, the scheme falsely accused welfare recipients of owing money to the government and issued debt notices to people identified through a process called income averaging, which compared their reported income with tax office figures.

More than $750 million was wrongfully recovered from 381,000 people.

Commission chair Catherine Holmes – a former Queensland Supreme Court chief justice – said those who were meant to be overseeing the program had questions to answer.

“Many people at different levels of government will be asked to give an account of their role … with the robodebt scheme,” Ms Holmes said.

“But the focus … will be on those in senior positions, who had or should have had oversight.”

Former prime minister Scott Morrison, Alan Tudge and Christian Porter all oversaw the scheme at times.

The scheme was ruled unlawful in 2019 and a settlement of $1.2 billion was reached between robodebt victims and the former coalition government in 2020.

Ms Holmes urged benefit recipients who had been chased for debts through the scheme to come forward with their experiences.

“This was a difficult, stressful time in the lives of thousands of people who were told they had debts to pay,” she said.

“I understand many just won’t want to revisit the experience, but submissions by those who are prepared to describe what happened in their case will be very helpful indeed, in establishing the detail and the human impact of what occurred.”

Speaking on Tuesday morning, Government Services Minister Bill Shorten called it “Australia’s greatest failure of public administration in social security”.

“It was a scheme which said it was targeted for getting Centrelink cheats to pay what they owed … the truth of the matter is the scheme was unlawful,” he told reporters.

“Once a machine … a faulty algorithm, asserted a debt was owed, the onus was reversed and the citizen had to prove why the government was wrong.

“These were David and Goliath struggles.”

Labor promised to call the royal commission before the election and followed through soon after winning.

The inquiry is expected to examine how the scheme came to be and why warning signs were ignored by a string of coalition ministers.

It will also examine the use of third-party debt collectors and others concerns raised.

– AAP