The federal government is imposing a cap of 15 days on holding prisoners in solitary confinement, but some say the move is not enough to meet the international bar for human rights.

Under a new bill tabled in the House of Commons Monday, Correctional Service Canada will have an 18-month transition period, during which time the cap will be set at 21 days, after it passes in to law.

"The objective is to contain that to the absolute minimum. I don't believe that should be part of our process. We're moving away from it," Public Safety Minister Ralph Goodale told CBC News Network's Power & Politics in an interview with host Rosemary Barton.

He said the bill is part of an overall move by the government to address issues related to inmates with mental illness, the over-representation of Indigenous people behind bars and the overuse of segregation with policy, legal reforms, and budgetary spending.

Proposed time limits are subject to safety and security requirements, as well as ensuring reasonable alternatives are available.

Under the new legal regime, an independent external process will review when a prisoner is kept in segregation beyond the presumptive time limit, or if an inmate is placed in segregation for 90 cumulative days in a one-year period, more than 3 times in a year when the 21-day limit has been extended due to circumstances such as security.

'Weak step'

Mary Campbell, a criminal justice expert and former director general of the corrections and criminal justice directorate at Public Safety Canada, said the United Nations has established 15 days as the limit, yet the Liberals are phasing in with a 21-day cap.

"Are we legalizing torture for another two years? I think we can do better than that," she said.

Calls for tighter restrictions over solitary confinement grew louder after the high-profile inquest into the death of teen prisoner Ashley Smith.

Smith died in a segregated prison cell at the Grand Valley Institution for Women in Kitchener, Ont., in 2007. A coroner's jury ruled that her self-inflicted choking death was a homicide and made 104 recommendations to prevent similar deaths in the future.

Some critics and prisoners' advocates have demanded a total ban on segregation, calling it cruel and unusual punishment.

The bill also includes a new provision to reinstate an offender's right to an oral hearing by the Parole Board of Canada after a suspension, termination or revocation of parole or statutory release. It would also make offenders who committed an offence before March 28, 2011, and who met the previous criteria for an accelerated parole review, now eligible.

Monday's announcement comes just weeks before a lawsuit challenging the practice of solitary confinement was scheduled to go to trial on July 4. The British Columbia Civil Liberties Association, which launched the legal action, is not commenting because the case is set to begin.

Minister of Public Safety, Ralph Goodale, says the government is putting in place new rules whereby segregation will now be capped at 15 days. 1:57

The John Howard Society of Canada has called for an end to the use of prolonged segregation, which is anything longer than 15 consecutive days and no more than 60 in a calendar year. It has also said that people with serious mental illness or suicide risks should not be placed in segregation.

In March, Canada's correctional investigator Ivan Zinger found that Correctional Service Canada was holding fewer inmates in solitary confinement and for shorter periods of time.

But he called on the federal government to implement legislative reforms to ensure the positive momentum was maintained to further ease reliance on segregation, especially for inmates with mental health problems or those who are prone to hurting themselves.

Inmates in solitary on decline

Zinger said on any given day there are about 400 inmates held in segregation, about half the average of 800 just a few years ago. He said the creation of special needs and mental health units has led to the drop.

He called today's bill a "positive step" to further limit the use of segregation and have an independent oversight of the process.

"I believe it will put Canada at the forefront of best correctional practices in the world," he told CBC.

But Zinger pointed to significant gaps in the system. He believes certain groups or individuals, including the severely mentally ill, younger offenders aged 18-21, suicidal, palliative patients, or pregnant women should be prohibited from being placed in segregation.

"That will be left to policy, and that's a shame. It should be brought into legislation," he said. "That is what is most difficult to accept in our correctional system, that people who suffer from mental illness can be segregated and placed in what is basically solitary confinement for days and sometimes months."

A report from Zinger's office released earlier this year found the average length of stay in segregation has decreased from 44 days in 2007-08 to 26 days in 2015-16.

Today there are 399 inmates in segregation, including 94 who were there for over 60 days, he told CBC.