OTTAWA -- Public Safety Minister Ralph Goodale must explain why the Correctional Service of Canada waited three months to call police after learning of assault allegations at Nova Institution for women in Truro, N.S. last year, the federal Conservatives said Tuesday.

The federal correctional agency apologized Friday after facing questions from The Canadian Press about a previous public statement that asserted that "as soon as allegations of misconduct were brought forward we began our investigation and notified our police partners of the matter."

The agency now says it contacted police March 29, three months after it first learned of the allegations now at the centre of a lawsuit by three women -- delaying while it conducted an internal investigation of a corrections officer.

"We apologize for communicating the timing of CSC's contact with the police in error," it said Friday. "As the police are investigating, and this matter appears to be before the courts, we are unable to provide any further details."

Last week, Truro's police chief confirmed his force was already investigating the allegations on March 28. The correctional service said it wasn't aware of that when it made contact.

"When we contacted Truro Police they indicated that they had recently received a call," it said in a statement on Friday. "There was no indication made that an investigation was already underway."

Pierre Paul-Hus, the Conservative public-safety critic, said Tuesday that Goodale has to say why this "appalling situation" took place and ensure it never happens again.

"CSC clearly has the responsibility to immediately report allegations of sexual assault by their staff to the proper authorities," the Quebec City MP said.

"It is shocking that CSC would then try to hide the fact that they did not notify police until three months later."

In response, Goodale's office said Tuesday the minister has asked his officials to review the "appropriate and timely steps to be taken when a staff incident is being investigated which could also constitute a criminal offence."

The government can't comment on the particulars of the case as it is under investigation by police, spokesman Scott Bardsley said, adding that ensuring the safety and security of federal institutions, staff, victims and public is the correctional system's "highest priority."

"Sexual assaults are a criminal offence and cannot be tolerated in correctional facilities," he said.

Independent Sen. Kim Pate, the former executive director of the Canadian Association of Elizabeth Fry Societies, which advocates for prisoners, said Tuesday that it's "incredibly problematic" that the Correctional Service failed to call police for three months.

She said the failure to pick up the phone about allegations of a criminal offence underscores the extent to which the Correctional Service of Canada does not take seriously the rights --particularly the human rights and the charter rights -- of prisoners.

"The only way that you could explain this behaviour is if you actually didn't see the women as having rights and entitlements worthy of protection," Pate said.

It is "atrocious" that people in prison cannot expect to have protection of the law once they're there, she added. Inmates are incarcerated because they have been convicted of a criminal offence but that in no way grants a license for them to be further punished or victimized, she said.

"This is exactly why we need external, and particularly judicial, oversight of corrections," she said.

NDP public-safety critic Matthew Dube agreed on Tuesday the correctional service's response to the allegations of assault at Nova Institution speaks to the need for a culture shift.

"Them investigating themselves is far from sufficient on a variety of issues," said the MP for Beloeil-Chambly, southeast of Montreal.

"The responsibilities and -- perhaps I would dare say, at this point in this Parliament, the failure -- of the minister has been to institute the kind of change in culture that, I think, has long been required."

Dube also urged Goodale to find out what happened, adding it is "pretty disgraceful" that the service seems to have misled the public by implying it had contacted police immediately when it had not.