Centrelink staff working on the agency's controversial debt claw-back program have been told to ignore errors in calculations and push through debts they know are incorrect, according to an anonymous letter written by a person claiming to be a Centrelink compliance officer.

Key points: Letter claims Centrelink directed staff to ignore errors in debt calculations

Letter claims Centrelink directed staff to ignore errors in debt calculations Anonymous letter written by someone who says they work for Centrelink

Anonymous letter written by someone who says they work for Centrelink The Department of Human Services says the claims are not accurate

Activist group GetUp! released the eight-page letter it received from a person claiming to have worked on Centrelink's automated data-matching project, known as the Online Compliance Intervention.

"What is known to date is literally the tip of the iceberg compared to the true scope of the deliberate wrongful actions that are being deployed under the department's Online Compliance Intervention (OCI) review process, which is raising debts that are incorrect for far more reasons than anyone outside the organisation knows about," the letter said.

Welfare groups are pushing the Federal Government to suspend the project after a raft of welfare recipients claimed the automated system incorrectly matched their reported income with their tax records.

Letter claims 'multitude of errors'

The anonymous letter said a small percentage of the debt notices require manual intervention by compliance officers.

"And this is where we as officers are seeing the multitude of errors that are leading to debts being raised incorrectly," it said.

Time to adopt a lighter touch? In the wake of the debt recovery debacle, Helen Hodgson asks if it is time for Centrelink to change tack. Read more Read more "Compliance officers like myself are bound by tight rules that direct us to leave duplicated income, not correct debts based on income already provided by customers, leave in income that is legally not assessable, not correct debts for income that has been declared and coded to other parts of our system based on how we break up income … and leave in information that is doubled up."

The author said they wrote the letter "because I along with so many of my co-workers have tried to stop the wrong that is being done to thousands of our customers on a daily basis and I can no longer live with what we are doing".

7.30 has been unable to establish the identity of the author of the letter, nor verify all its claims.

However, several past and present staff members have corroborated parts of the letter, including the claim that OCI system is incorrectly tallying up payments that are usually treated as non-assessable income.

Do you know more about this story? Email mcgrath.pat@abc.net.au

"It puts back in all the income that is exempt from assessment and staff are not allowed to fix it by removing it," the letter said.

"Debt[s] are being raised solely on a year or more of exempt income."

GetUp! campaign director Mark Connelly defended his organisation's decision to release the letter without verifying its claims.

"On our own, we don't have the resources to confirm every claim in the letter," he said.

"By publicly releasing the letter today we allow journalists to confirm the claims with their sources, inspire other sources to come forward with critical information, apply pressure for an immediate parliamentary inquiry, and allow the Government to confirm or deny any of the claims in the letter, among other avenues of investigation."

Government says claims are not accurate

The Department of Human Services has denied several of the claims in the email.

It said recipients were not assessed on the basis of doubled income.

"We give those who receive a request for information an opportunity to review, confirm or change these details in the online system," the department's general manager Hank Jongen said in a statement.

However, this does not deal with the key claim in the letter that recipients are often unable to identify that doubled income has been included in the calculation.

The department also said non-assessable income was not included in debt assessments.

However, 7.30 has already reported the experience of George Birkett, who had more than $7,000 in non-assessable income erroneously included in his debt assessment.

This was removed after his story was aired on the program.

The department also insists Paid Parental Leave assessments are made in accordance with the applicable legislation.

"Some of our staff believe that intensive one-on-one management of recipients is always required ... some staff do not welcome technology driven change," Mr Jongen said.

"We will continue to work with staff to explain how the system operates and the role they play."

The department published their full response to the claims on their website.

Letter claims compliance officers instructed to ignore errors

The letter also claims compliance officers have been instructed to ignore errors generated by the OCI's "fuzzy matching logic", which compares employer names reported to Centrelink with the names welfare recipients have reported to the Australian Tax Office (ATO).

The letter claims the system is duplicating recipients' estimated income when there is a mismatch between the two company names.

"The official response was that these are correct and no one is permitted to fix them," the letter said.

The letter includes what purports to be an internal memorandum to staff, justifying how similar employer names will not be picked up by the OCI system.

The memo said "in these cases the system is working". It instructs staff where they see a failure to match similar employer names not to alter the outcome. Instead they should direct the welfare recipient online, and they should not report the error to the internal OCI Helpdesk.

The letter also said: