Fallout from a damning Australian National Audit Office report that found more than a quarter of customer calls made to Centrelink got a busy signal and never even made it through to the switch is continuing to reverberate.

Labor’s Human Services shadow Senator Doug Cameron has mounted a fresh attack on Human Services Minister Senator Marise Payne on the back of a Joint Committee of Public Accounts and Audit hearing looking into the audit released in May, rejecting suggestions that the complexity of the welfare system and problems with digital services were the cause of the issue.

“Senator Payne has taken her eye off the ball in the face of persistent complaints from Centrelink clients that telephone call waiting times are getting longer and that the MyGov web portal is not capable of meeting a large number of clients’ needs,” Senator Cameron said.

The Opposition is gunning for the Human Services Minister as the Department of Human Services continues to try and get more people to use its online services, a switch that can save millions in call centre and office staff costs when it works    but goes horribly wrong when it doesn’t.

While it is still unclear what the ultimate cost of remediating the call centre short staffing may come in at, there is mounting internal public sector concern that frog marching customers onto inadequately tested digital services could potentially generate additional downstream costs as well as sending satisfaction rates down.

The Australian Taxation Office came in for a pasting from customers at the beginning of the new tax year when its online myTax lodgement services had a hard time coping with heavy traffic loads, a situation in large part cause by the bottlenecking of transactions.

Senator Cameron is now calling for more transactional channels to be made available until things teething problems and glitches are sorted out.

“A range of effective channels including telephone, online and face-to-face contact must be readily available to Australians seeking to engage with Centrelink. Over-reliance on less than perfect digital channels is causing distress to many Centrelink clients,” Senator Cameron said.

“There is also a clear need to get staffing levels right, particularly the balance between permanent and casual staff numbers and making sure that frontline staff have the requisite skills and decision making authority to provide truly citizen-centred service delivery.”

Senator Cameron also took a swipe at frustrated enterprise bargaining talks across the public service as a distraction inside Human Services.

“For the past 18 months, [Human Services] has been mired in the Abbott Government’s unfair and disastrous public service workplace bargaining policy.”