VANCOUVER — The B.C. Civil Liberties Association and the John Howard Society of Canada are suing the federal government over the use of solitary confinement for prisoners.

The groups say segregation for up to 23 hours a day for months or years at a time amounts to cruel and unusual punishment and is internationally regarded as torture.

Their lawyer, Joe Arvay, says such confinements can occur without input from an independent decision maker to determine whether the practice is justified and that violates the constitutional rights of inmates.

The lawsuit to be heard in B.C. Supreme Court claims prolonged segregation is a risk factor for suicide behind bars, as was the case in the death of teenager Ashley Smith in an Ontario prison in 2007.

The civil liberties association’s senior lawyer Carmen Cheung says Canada has continued to rely on the practice when other countries have scaled back their use of a dangerous system.

Catherine Latimer, executive director of the John Howard Society, says solitary confinement is inhumane and is being used to warehouse mentally ill inmates.