TORONTO -- A proposed class-action lawsuit filed in an Ontario court Friday alleges the federal government fails to provide adequate care to mentally ill prisoners while relying far too heavily on solitary confinement as a way to deal with them.

The case, if certified by the court, would pit the Attorney General of Canada against federal inmates diagnosed with mental illness between 1992 and the present.

"Prisoners in federal institutions who suffer serious mental illness are not being given the treatment they are statutorily entitled to," said lawyer James Sayce, whose firm Koskie Minsky is behind the action. "It's a problem that can't be ignored anymore."

The lawsuit, which contains allegations not proven in court, is seeking at least $600 million in damages and estimates hundreds of mentally ill prisoners could be part of the action if it is certified.

"They are being warehoused and they are being subjected to extended periods of time in solitary confinement because the federal prison system doesn't know what to do with them," said Sayce. "The effect is...the illnesses get worse, and you have serious pain and emotional stress being suffered by these unwell inmates."

A statement of claim filed Friday alleges that those tasked with caring for mentally ill inmates in federal prisons have treated them with "contempt, prejudice, indifference and abuse."

It claims prison staff are unqualified to administer, control, protect and care for mentally ill inmates and instead rely almost exclusively on "force, compliance and behavioural inducement methods."

It also alleges that extended periods of solitary confinement are used to "contain and manage" mentally ill prisoners.

It alleges the practice amounts to "cruel and unusual punishment" for mentally ill prisoners and claims that the government is failing in its mandate to rehabilitated rather than punish prisoners.

"Federal penitentiaries are becoming Canada's largest repositories for the mentally ill," the statement of claim said. "Prisoners diagnosed with serious psychological disorders and illnesses have suffered severe harm as a result of the defendant's policies and procedures."

The statement of claim also alleges mentally ill inmates face interruptions in care when they are admitted to and transferred between institutions, which lead to them being denied medication for an extended period, and are also allegedly denied commonly prescribed psychiatric drugs.

A spokeswoman for Correctional Service Canada said it was in the process of reviewing the claim and could not comment on the matter as it was before the court.

"Ensuring the safety and security of institutions, staff, and the public remains the highest priority in the operations of the federal correctional system," said Veronique Riox.

"Canadian law and correctional policy allows for the use of administrative segregation in limited circumstances, when there is no reasonable alternative and for the shortest period of time necessary."

The representative plaintiff in the case, Christopher Brazeau, is a prisoner at an institution in Edmonton. The 34-year-old suffers from post traumatic stress disorder, generalized anxiety disorder and attention deficit and hyperactivity disorder, said the statement of claim.

He is serving a sentence of 12 years for robbery-related crimes. He has spent 12 consecutive months in solitary confinement, has gone long periods without his necessary medications and has "regularly" been prescribed unsuitable medications, the statement of claim said.

"Mr. Brazeau suffered significant worsening of his mental health problems during his time in solitary confinement, including anxiety, depression, self-harm, suicidal thoughts and visual and auditory hallucinations," the statement of claim alleged.

"It is likely that Mr. Brazeau's condition will continue to deteriorate as a result of Canada's failure to create and implement policies that allow for the provision of proper health care."