Several prisons in Saskatchewan, Alberta, Ontario and Quebec will be expanded as part of the Conservative government's five-year, $2.1-billion plan to increase capacity at federal institutions.

The government sent several cabinet ministers and MPs across Canada on Monday to announce the 634 new beds at facilities in Edmonton, Gravenhurst and Kingston in Ontario, Cowansville, Que., as well as at two sites on First Nations reserves in Saskatchewan.

The new beds are to accommodate an expected growth in the prison population from tougher sentencing provisions brought in by the Conservatives — including limiting the amount of credit prisoners get for time served in custody before and during their trial.

The Conservatives say the expansions will strengthen Canada’s prison infrastructure, provide construction jobs in communities across Canada and help keep dangerous criminals behind bars.

P.O.V.: Do you think Canada's prison system needs expansion? Take our survey.

"We've listened to Canadians, who are pretty aware of what's happening on our streets," Conservative MP Laurie Hawn said during a panel interview on CBC's Power & Politics with Evan Solomon.

"It doesn't make sense to put criminals back on the street simply as a cost-saving measure."

The Correctional Service of Canada anticipates adding 2,700 beds to men's and women's facilities across Canada in the coming years.

Bigger prisons 'wrong approach': MPs

Opposition Liberals have criticized the Conservatives for going ahead with plans to spend billions on "U.S.-style mega-prisons" at a time of declining crime rates and a record federal deficit.

Liberal public safety critic Mark Holland said similar policies have been a "complete disaster" in jurisdictions such as California, which has seen its penitentiary costs skyrocket.

"It nearly bankrupt the state," Holland told the CBC's Solomon. "They have no money for education, health care, for infrastructure."

Opposition MPs also accused the government of cutting funding for programs aimed at crime prevention and supporting victims of crime, despite a multimillion-dollar advertising campaign to promote them.

New Democrat MP Joe Comartin said the government should be spending money to fix existing prison problems, including lack of staff and support for addicts and the mentally ill.

Instead, Comartin said, the Conservatives are basing their corrections policies on political ideology rather than sound factual analysis.

"Every social scientist who has looked at this area is saying this is the wrong approach to take," he said.

In July, Statistics Canada reported that "both the volume and severity of police-reported crime fell in 2009," three per cent from 2008 and 17 per cent from 1999. The Tories have dismissed the report's findings, saying other studies show a rising number of crimes that aren't reported to police.

Public Safety Minister Vic Toews has said Canada's crime rate is still "unacceptably high."