Public servants at the agency continued to taken away from their regular work this week to field calls from irate parents struggling with the new system but the Department of Human Services, which runs the CSA, says everything is business as usual within the agency.

Agency staff report the new system, called 'Pluto' and supplied by multinational computing giant SAP, is slower and clumsier than the obsolete technology it was supposed to replace and public servants have described the launch as a "shambles" a "shit show" and a "cock-up".

The practice of diverting officers from normal duties to take phone calls is known as an escalation or an emergency escalation and Human Services has refused to confirm there have been escalations and denied there have been emergency escalations.

The main workplace union, the CPSU, says 'all hands on deck' emergency escalations to phones have been daily events as the slower system is impacted on call wait times, that the escalations were lasting for days and creating huge backlogs of work.

An internal memo from a senior Child Support Agency official, obtained by Fairfax Media, gives some sense of the strain imposed on frontline officials since the new "Pluto" system began operating in late April.

On June 19, Kate Hay, the general manager of the agency's call centres, wrote to her staff thanking them for their "understanding and commitment" during the roll-out of the new system.

"The executive and I acknowledge that this extremely busy period has meant that some of you feel that you are not on top of your work as you would like to be, please be assured that we realise that you are all doing your best to manage this and seeking assistance to manage some aspects which may not be within your direct control," Ms Hay wrote.

"We also note that there have been more escalations required recently to meet our demand which, can seem disruptive to your day.

"Please be assured we remain committed to meeting the needs of our parents, managing all of our work and supporting you."

Ms Hay's message to staff appears at odds with the department's claims made on June 22, that additional staff had been rostered on to take calls while other public servants were trained in the new system.

"Additional staff to support training are not escalations or emergency escalations," the department's media unit claimed at the time.

In response to questions about Ms Hay's memo, Human Services issued another denial.

"The department refutes any accusation of a cover-up or that managers are not following correct procedures during this transition," the department said in a statement.

"The statement made by Ms Hay is in reference to rostering escalations.

"This is part of our routine business processes to manage demand."