More stories continue to emerge of people being wrongly issued with debt review letters from Centrelink.

Some people are now saying they were so confused or intimidated by the letters, that they opted to pay the debt they don't believe they owe.

The former head of the government's Digital Transformation Agency has said the error-rate within Centrelink's automated debt recovery system is so high it would send a commercial operation out of business.

Paul Shetler was personally hired by Malcolm Turnbull in 2015 to reform the government's digital operations, but he quit in November after just 18 months in the job.

He says the Centrelink debacle represents not just an IT failure, but a management and political failure as well.