When Auditor General Michael Ferguson delivers his second report on the federal government's failed Phoenix payroll system on Tuesday, public servants and their unions hope to get more answers about who was responsible for the decision to launch the new pay project before it was ready.

Earlier this month, Public Services and Procurement Canada (PSPC), the department in charge of paying federal workers, said there were still 372,000 financial transactions beyond normal workload.

Tens of thousands of public services employees have been overpaid and underpaid since February 2016 when the Phoenix system was initiated under a contract with IBM.

Due to the pay problems, many term-workers, retirees, students, workers on parental leave and full-time employees are still trying to resolve individual problems with the federal pay centre, the Canada Revenue Agency and various other departments.

"We haven't been focused on blame, because we have to focus on getting people paid," said Debi Daviau, president of the Professional Institute of the Public Service of Canada. "At the end of the day, somebody ought to wear this, and I think it's really important that we establish who that is."

Debi Daviau, president of the Professional Institute of the Public Service, says she hopes the auditor general establishes who is to blame for the $1 billion Phoenix fiasco. (CBC)

Daviau said she was disappointed with the scope of the first auditor general's fall report on Phoenix, as it didn't "delve into things like bad contracting practices and issues at the conception of this project."

The government has conceded that it is now looking for a replacement to the now two-year-old pay system, and yet the costs for Phoenix continue to rise.

This spring, PSPC reported the combined cost of implementing and fixing the ailing program has exceeded $1 billion.

Erika Aruja, an economist now working in the private sector, has been caught up in the Phoenix fiasco since shortly after the new pay program was launched.

Aruja, a former employee at Environment Canada was overpaid for months. She repaid $17,000 in a lump sum, but is still trying to get the government to reconcile the taxes and backpay still owed to her.

"So I can't walk away, because I want my money back. I also need my taxes back, because it's not cool for the CRA to think that you owe money," said Aruja.

"I work in the private sector. They pay me properly and on time and consistently. It's shocking to me that people haven't walked off their jobs."

The largest union representing federal government employees, the Public Service Alliance of Canada said it also anticipates that this report from the auditor general will point to top bureaucrats responsible for giving the green light to Phoenix — knowing that the fledgling project was experiencing errors and failed tests.

The union says if it isn't satisfied with the answers provided in Tuesday's auditor general's report, it is prepared to call for a national public inquiry into Phoenix.