Minorities make up a disproportionate percentage of the country's prison population, but the faces of the guards don't match the faces on the other side of the bars, Canada's prisons watchdog said Tuesday.

While the racial makeup inside the corrections system is changing, prison hiring practices have not kept pace, correctional investigator Howard Sapers said as he released his office's latest annual report to Parliament.

Sapers points out that close to a quarter of all inmates are aboriginal even thought they make up only four per cent of the general population.

"Recent inmate population growth is almost exclusively driven by an increasing number of aboriginal and visible minority groups behind bars," he said.

"Today, four in 10 of the federal inmate population is comprised of non-Caucasian offenders."

As well, he says, black inmates are over-represented, particularly in maximum-security institutions.

Black offenders also report facing discrimination by being marginalized or even shunned from within the corrections system, he said.

Cultural clash

He outlined an example of a cultural clash involving a prison literacy group where the majority of the participants were black.

The book up for discussion was Mark Twain's The Adventures of Huckleberry Finn.

"While this novel is considered a classic, it is riddled with racist terminology," the report said. "Black inmates were made to read racist words aloud that they described as 'degrading' and 'demeaning.'"

The novel was only replaced after some prisoners protested and refused to take part in the group.

Sapers called on the federal government to develop a national diversity-awareness training plan and hire new staff responsible for building networks between the prisons and outside cultural groups.