Centrelink has removed advice telling welfare recipients they only needed to keep payslips for six months, which conflicted with the government’s efforts to claw back debts from up to six years ago.

The pressure on the government over problems with its automated debt recovery system continued on Tuesday, as the Greens called for the issue to be referred to a Senate inquiry.

Senator Rachel Siewert urged the government not just to suspend the system, but to scrap it altogether, saying it had caused “too many issues to remain viable”.

“When parliament resumes I will work with Senate colleagues to initiate a Senate inquiry into the debacle,” she said.

“We need clear answers on how this program went so wrong and what the real implications are.”

The Community and Public Sector Union, which represents Centrelink workers, say its members have repeatedly found the debts are being wrongly issued.

The assistant national secretary, Michael Tull, said staff were already “desperately overstretched”, and that the problems with the debt recovery program were piling on “even more pressure and feeding more aggression from understandably frustrated customers”.

He called for the system to be immediately suspended.

“We hold very serious concerns about Centrelink’s ability to cope in coming months,” he said.

“There’s a perfect storm of work coming, with this debt recovery scheme likely to be just part of the problem.”

The system, as it has done for years, relies on data-matching between Centrelink and the Australian Taxation Office to detect discrepancies in income. But where humans would have previously examined those discrepancies, Centrelink now automatically demands individuals prove they were entitled to benefits within 21 days using its online system.

Those debts could be up to six years old, and new laws will allow the government to pursue debts even further back. Up until at least last week, the Department of Human Services website informed customers they only needed to hold payslips for six months as proof of income.

“You need to keep evidence of your earnings as we may ask you to show proof of your income. We recommend keeping your payslips for at least 6 months,” it read.

Users on social media noticed the flawed advice, and also noticed this week when it was quietly removed.



Now, the advice simply reads: “You need to keep evidence of your earnings as we may ask you to show proof of your income.”

The Department of Human Services general manager, Hank Jongen, who is effectively head of communications, said the phrase was identified as potentially confusing.

“The Department of Human Services website consists of more than 1,300 pages and around 475,000 words of content for customers,” he said.



“The phrase in question was drawn to our attention and deemed to be potentially confusing, so it was removed.”



Human services minister Alan Tudge, who has now returned from leave, issued a statement on Tuesday defending the system.

Tudge said Centrelink had been using data-matching for years, and all it had done was make it more automated.

“The only major change is that it is more automated so we can complete more checks,” he said. “Where there is a discrepancy between the tax office information and the self-reported Centrelink information, a notice requesting clarification is sent to the welfare recipient.”

“It is only after the recipient has clarified the discrepancy or ignored the notice, that any debt may be calculated.”

He said individuals can call Centrelink’s phone lines for assistance at any point. Those phone systems have seen lengthy wait times, and an audit in 2015 found almost a quarter went unanswered.

Tudge said individuals were given at least three opportunities to ensure their employment income was accurate.

“Firstly when the request for information is sent, secondly they can request a review of any debt that is raised, and finally by appeal to a tribunal,” he said. “Labor is demanding we cease a process that has successfully recovered over $300m of incorrectly paid taxpayer’s money since July and, frankly, I don’t think many taxpayers would support that call.”

Labor’s Linda Burney continued to criticise the system on Tuesday, saying it must be suspended.

“Sending out 20,000 letters a week, potentially 4,000 of those letters are mistakes, is crazy,” she said. “It is not the way in which public policy should be exercised.”

She described Centrelink as “at breaking point”, and said its staff were being put under immense pressure and were not to blame for the government’s “cash grab”.

When asked whether Labor would support a Senate inquiry, Burney said she had already referred the issue to the auditor general, and highlighted the recently initiated commonwealth ombudsman investigation.

She said she expected to receive communications from the auditor general next week.

Tull said CPSU members tasked with reviewing cases had found serious problems with the debt recovery system.

“We have members in Centrelink who’ve been tasked with reviewing cases through this scheme saying in almost every case the poor customer ends up owing nothing, or just a fraction of the debt claimed,” he said.

“In at least one case an initial debt for $9,000 ended up being $90. That’s not a minor discrepancy but a clear sign of a failed system.”

That accords with the recent story of a Centrelink compliance officer, who told Guardian Australia that of the hundreds of disputed cases reviewed, only about 20 were legitimate debts.