A sex for drugs investigation is underway at the Grand Valley Institution for women. It’s alleged to involve a male guard and at least one female inmate.

It’s reported, a guard at Grand Valley has been suspended.

Corrections Canada now conducting an internal review of anonymous complaints made by at least one inmate, but one advocate is calling for an external review of the situation.

The executive director for the Elizabeth Fry society, Kim Pate says, "There were concerns being raised that a staff member at Grand Valley Institution, a male staff member had been engaged in sexual activity with one of more women in the prison and the allegations that was in exchange for drugs or tobacco."

Pate says when she heard the allegations a few weeks ago, they were documented and presented to the warden and a corrections Canada investigator.

A spokesperson for Waterloo Regional Police says they're not involved and union officials are declining comment until the investigation is complete.

Pate admits these investigations are difficult for Corrections Canada and the complainants may not want to come forward but she's again calling for a review of male guards in women's prisons.

"It's a place that makes women more vulnerable and puts them in a greater position of potentially being abused again if in fact there is somebody in the institution who would abuse their power in that way” say Pate.

Corrections Canada says if there has been illegal activity the appropriate action will be taken.