A hearing into Centrelink's automated debt recovery system has revealed the emotional impact the troubled system has had on Australians, a senator says.

Western Australia Greens senator Rachel Siewart, chair of the parliamentary committee leading a Senate inquiry into the system, says Monday's hearing in Adelaide shed light on people's experiences.

The inquiry previously heard that more than 200,000 people had been affected by Centrelink's so-called robo-debt program and at least one in five debt notices issued had been incorrect.

"It's one thing to know about it. It's another to hear people talk of the emotional impact it has on themselves and on the organisations that are supporting people," Senator Siewart told AAP.

"It's developing up a clearer picture to help us understand the emotional impacts and the stress this is placing on individuals."

She said the hearing also highlighted the role Centrelink's income averaging processes have played in problems with its debt notices.

And she said the Department of Human Services has not properly grasped how significant this has been.

"They don't seem to understand the enormity or the impact this is having on people or the fact that the averaging is having an impact."

Senator Siewart said the department couldn't confirm whether certain demographic groups have been affected by debt issues more than others, but this is likely to become clearer later.

"Certainly people are pointing out that this is particularly hard for people on low incomes and ... (those who) are vulnerable," she said.

The Legal Services Commission of SA, SA Council of Social Service, Anti-Poverty Network SA and Youth Affairs Council SA were among the groups that attended the hearing in Adelaide.

The Commonwealth Ombudsman also released a report on Monday calling on the Department of Human Services to make its automatic debt recovery system more user-friendly and transparent.