The union announced Wednesday that it is seeking an injunction to halt the Social Assistance Management Software that was installed Nov. 12.
The $240 million software is responsible for a series of overpayments to recipients, but also continues to cause delays in processing financial assistance.
"Despite our repeated warnings, the Ministry of Community and Social Services went ahead and implemented this system, which in turn disadvantaged the most vulnerable people in this province," union president Warren (Smokey) Thomas said in a news release.
Staff feels 'helpless"
Thomas said the union will also pursue a declaration that the government violated the rights of social assistance recipients under the Canadian Charter of Rights and Freedoms by implementing a system it knew was flawed.
According to the union, it is still possible to return to the old system while the problems with the new software are fixed.
"Our members, working in both programs, are doing their absolute best to try and minimize the impacts, but in spite of their best efforts the number of program flaws grows by the day, and staff are beginning to feel helpless," Thomas said.
Premier Kathleen Wynne said earlier this month that the upgrade was necessary because there was an outdated system in place that needed to be upgraded. The government also said most of the problems had already been fixed.