OTTAWA — It is time for the federal government to ditch the problem-plagued Phoenix pay system and build a new system that works, using public servants, says the head of one of Canada's largest public service unions.

In a press conference Tuesday, Debi Daviau, president of the Professional Institute of the Public Service of Canada, which represents many of federal IT specialists, called on the government to kill the federal payroll program, and use its own people to build a new system.

Daviau says public servants have lost confidence in Phoenix, and those who are currently triaging the bugs within the system are the ones now telling their union that it can't be fixed. She says she's heard from members that could deliver a new system faster than they estimate it'll take to fix Phoenix, though PIPSC does not have an estimate on what that approach would cost.

In an interview on CTV's Question Period that aired Sunday, Public Services and Procurement Minister Carla Qualtrough said she couldn't guarantee that the price tab to fix the problem-plagued pay system won't hit a billion dollars. Qualtrough also said she doesn't know when the system will be consistently paying people correctly and on time, though she anticipates the number of backlogged cases to go down in the New Year.

"The government needs to stop throwing good money after bad and start investing in a system that works," Daviau said Tuesday.

The Phoenix system, initiated by the previous Conservative government in 2009, was meant to streamline the payroll of public servants and save more than $70 million annually. Already, the government has planned to spend $400 million trying to fix it, including hiring more staff and setting up satellite pay centres in Gatineau, Montreal, Winnipeg, and Shawinigan, to try to chip away at the pile of remaining cases. It cost $309.5 million to implement the system.

PIPSC says the government needs to hire more people in the short-term, while tasking its own IT people with building a new pay system. She said there is internal expertise, untapped when Phoenix was first conceived, that could help design a system that works for the intricacies of the federal public service.

The initial promise from the department was to have the backlog of problematic pay cases resolved by Oct. 31, 2016.

As of Oct. 18, there were 265,000 cases of employee pay issues left to be resolved, and the department says more than half of public servants who get paid through the system are still experiencing "some form of pay issue."

Though PIPSC's numbers show that the number of open cases of pay problems is closer to 330,000, PIPSC said Tuesday.

“We are listening to concerns and issues raised by employees, and we are committed to working collaboratively at all levels to resolve them as quickly as possible. PSPC continues to work with all partners including union leadership to find innovative and efficient solutions to the pay issues,” said Ashley Michnowski, a spokesperson for Qualtrough in an emailed statement.

PIPSC estimates it would take approximately a year to configure and test a new system.

"They've tried everything," Daviau said, when asked why she thinks the government might be more amenable to this solution now.

"We need our members paid and we need them paid as quickly as possible and we believe this is the quickest route to that state," she said.

The NDP are supporting PIPSC call for an alternative plan to produce a working payroll system.

“It is important that the experience and expertise of public servants in charge of remuneration as well as unions should be at the centre of formulating this plan B. The government cannot repeat the same mistake of ignoring warnings from unions and public servants,” said NDP deputy labour critic Karine Trudel in a statement.