TORONTO - A public servants' union is taking the Ontario government to court over what it calls a "flawed" computer system responsible for social assistance payments.

The new, $240-million Social Assistance Management System (SAMS) erroneously queued up $20 million in welfare and disability support overpayments earlier this month.

The Ontario Public Service Employees Union, which represents caseworkers responsible for administering social assistance payouts, says others who depend on social assistance got far less than normal or didn't get any payment at all.

OPSEU says the problem isn't with its workers but with the computer system, which it says it warned the government would not work properly.

The union has filed an application with the Ontario Superior Court asking for an injunction to stop use of the SAMS system until it can provide "reliable, timely and accurate benefits."

Social Services Minister Helena Jaczek has said the fact that some people got less than normal, or no payment at all, was not related to the glitch with the new system.