New figures show both the number of debts raised and the dollar figure raised through online compliance have shot up this year, while the number of debts reduced or waived has dropped.

About 193,000 debt notices were sent out this financial year to March 31, according to departmental statistics released to a Senate estimates committee. It's an 18.5 per cent increase on the total number of debts raised in the full 2017-18 financial year.

The total amount of debt raised has increased at a faster rate, jumping from $376.8 million in 2017-18 to $552.2 million so far this year, an increase of 46 per cent.

The amount of debt raised is not the same as funds collected, with just $74 million collected so far this year.

At the same time as debts have gone up, the number of debts waived, either in part or fully, has plummeted as a proportion of the overall number of debts.

Last year 5.7 per cent of debts were fully waived, while 6.4 per cent of debts were partially waived. So far this year just 4.5 per cent of debts have been fully waived and 5.8 per cent of debts partially waived.

Less than 5 per cent of debts raised have been reduced, according to the department's figures.

The increase in debts raised tallies with the experience of Welfare Rights Centre executive director Katherine Boyle, who says demands for the centre's robodebt services has jumped in the last six months.

Ms Boyle said she couldn't identify the cause of the increase in demand, but said it took time for changes in government policy to be felt at the centre, because people don't always know they can seek legal help.

"There's usually a long lag time between what the government does and what we see in our case work," she said.

Ms Boyle said that while she had not experienced a change in the way Centrelink handles robodebt reviews and cases, clients had.

"Just today we were discussing a case where someone has told us they had requested a review, I think it was seven times, and [Human Services] refused to refer it to an authorised review officer to review the evidence they provided, which they say means the debt should be vastly reduced or shouldn't exist at all, she said.

"That's a client trying to do it on their own. We haven't experienced a problem requesting a review."

Department of Human Services spokesman Hank Jongen said the continual improvement of the program had led to better outcomes for people reviewing their debts.

"A new assessment tool automatically filters out cases that are likely to result in either a zero or low value debt outcome. This is done before a review starts, meaning we can finalise the case without involving the customer," he said.

The new tool was introduced in July last year.

"We've also made it easier for people to engage with us as part of their review. The sooner we can work with someone on their review, the sooner it can be completed. The Commonwealth Ombudsman noted that customers are receiving better service through direct access to a dedicated helpline, which has very short wait times."

The department has reduced the number of reviews at times as it tests changes to its online compliance process.

The Australian Council of Social Services has labelled the new statistics "deeply concerning".

"The error-riddled robodebt system is causing extensive harm and eroding public confidence in government services, particularly among people who are most vulnerable in our community. Robodebt must be replaced with a more humane system of debt recovery," director of policy Jacqueline Phillips said.

Ms Boyle is concerned the Welfare Rights Centre's ability to help people affected by robodebt will be reduced, after the centre's funding allocation from the NSW government was reduced by $55,000.

Under a new process where the centre had to tender for state government funding the amount given was reduced without explanation.

Ms Boyle said that the centre was looking at redundancies and a reduction in services in the 2020-21 financial year due to the cuts.

People will have to wait longer to get an appointment, and fewer people will be able to access representation if the funding cut stays in place, Ms Boyle said.

"[Clients] will find it first of all much harder to get through to us. We have had clients say contacting you is like contacting Centrelink, which is heartbreaking."

In February 90 labour hire staffers began work in the Human Services debt management branch, after 80 public servants in the area were told their contracts wouldn't be renewed.