OTTAWA—The head of Canada’s federal corrections system says he’ll need to spend about $2 billion to deal with the influx of prisoners coming from the Conservatives’ law-and-order agenda.

“The primary impact of the legislation will be a significant and sustained increase to the federal offender population over time,” said Don Head, commissioner of Correctional Service Canada. “This will be particularly evident in the short to medium-term.”

Head said the crime legislation will mean an extra 4,478 people in federal prisons across the country over the next three years, on top of growth in prison population that would normally be expected.

He’ll have to hire thousands more staff, as well as renovate and expand existing prisons to handle the growing inmate population.

Plus, he says he’ll have to spend on programs that help prisoners cope, since the surge will require far more double-bunking — a practice that experts say often incites violence and discontent.

Head’s $2-billion estimate is lower than costs projected by the Parliamentary Budget Officer, but far higher than costs initially projected by federal ministers.

Head warned that federal prisons are increasingly becoming homes for the mentally ill, and his personnel are struggling to handle the new dynamic.

“Unfortunately we have become the default mental-health system in the country,” he said.

NDP critic Don Davies noted that Head’s $2-billion estimate was only the extra jail costs for two pieces of federal legislation, while many other pieces still have to be analyzed.

Davies said he wouldn’t be surprised to see costs rise much higher.

“It’s going to cost billions of dollars to implement just a small part of the government’s crime agenda,” he said.

At the same time, the government has not been able to show that putting more people in jail will cut down on crime, Davies said.