Centrelink's automated welfare-debt retrieval system has mistakenly sent bills of up to $24,000 to welfare recipients, warning them that debt collectors would be called unless payment was received.

As a result of the mishap, the minister has been accused by the Labor Party and Tasmanian independent MP Andrew Wilkie of preying on Australia's most vulnerable individuals.

The Commonwealth Ombudsman has launched an investigation, and the former head of the Digital Transformation Office, Paul Shetler, has said that, were Centrelink a commercial enterprise, its high data-matching error rate would have sent it out of business.

Damaging criticism and publicity like this normally would have a minister rushing to initiate a review, or at the very least expressing regret for any (unintended) distress caused.

But Mr Porter has remained his usual phlegmatic self, saying the letters sent initially to welfare recipients were "polite" and that only a “small” number of people had been asked to refund money they did not owe.

He also managed to reiterat his belief that the program was working well, and said it would be extended further to recover nearly $4 billion in welfare debts over the next four years.

Such insouciance may be attributed to the Coalition's belief that taxpayers hold welfare recipients in low regard, and that they reserve particular contempt for people rorting the system.

Conversely, it might indicate Mr Porter's resolve and confidence that this initiative – which matches Centrelink payments to Tax Office income data to determine if individuals have been overpaid – is fair and equitable and that it will deliver a much-need fillip to government finances.

Yet, as Mr Shetler has intimated, and as Peter Martin detailed in the article below, the debt-recovery program is susceptible to errors.

Mr Porter's reluctance to admit that possibility is troubling, particularly as workers who receive family tax benefits, and age pensioners, are next in line for data matching.

This blowback may be a taste of further things to come for Mr Porter.