As thousands of inmates cast their ballots Wednesday in the federal election, CBC News has learned a group of inmates in Canada's largest prison for women are planning legal action after being denied the vote in last year's Ontario provincial election.

Seven women in maximum security at Grand Valley Institution in Kitchener, Ont. did not vote in the 2018 provincial election because of an "administrative error" at the prison, according to Correctional Service Canada (CSC).

The prison staff member who was supposed to hand out registration forms and special ballots failed to do so in time, CSC told CBC News.

Inmates with Canadian citizenship and who are over age 18 have the right to vote in federal, provincial and some municipal elections.

A Supreme Court decision in 2002 ensures offenders have the right to vote under Section Three of the Canadian Charter of Rights and Freedoms.

Prison apologized

After the women in maximum security were not able to vote, the Elizabeth Fry Society started receiving calls from them.

Jessica Hutchison, who works for the inmate advocacy group in Waterloo region, was one of the people who responded to the messages.

"The women in maximum security are literally the most segregated and most vulnerable women in the prison … they are dependent on the staff there," said Hutchison.

"I just find it disconcerting that communication and processes were not in place in the months leading up to the election."

Jessica Hutchison, advocate for the Elizabeth Fry Society in Waterloo region, said she wouldn't be surprised if inmates in maximum security at other prisons have also had issues voting. (Julianne Hazlewood/CBC)

Next came an apology. Staff at the prison admitted their mistake to the women.

"[They] explained the error to the seven inmates and apologized for the error," said a statement from the correctional service.

Despite the prison's attempt to make amends, six of the women moved forward with legal action.

According to their lawyer Christopher Fleury, no claim has been filed yet but he expects to do so by the end of the year.

Fleury believes the case is the first of its kind since the court decision 17 years ago.

"As far as I'm aware, there hasn't been a case [of inmates] being denied the right to vote."

Correctional service responds

CBC requested an interview with the warden at Grand Valley Institution and the liaison officer, who would have overseen the 2018 voting, but the request was denied.

Correctional Service Canada said in a statement, "Grand Valley Institution has taken extra steps to ensure that the elections processes and deadline at the federal and provincial level are communicated to staff responsible for overseeing voting at the institution, as well as each inmate.

All offenders in all security levels have been provided a briefing on voting in the federal election."

A spokesperson for Elections Ontario also said it's confident the prison has identified the problem and is hopeful "the issue will not be repeated in future elections."

It added "we fulfilled our mandate of supplying special ballot application forms to all penal institutions in the province."

Voting day for inmates

It's unclear how many Canadian inmates will vote Wednesday but in the 2015 federal election, 44,296 inmates were eligible to vote and 20,673 cast a valid ballot, according to Elections Canada. That is a voter turnout of 46.6 percent, while the overall national voter turnout was 68.5 per cent.

Inmates have to select one of four options on where their vote will be counted:

The residence where they were living before they were incarcerated.

The residence of a partner or dependant who they would have lived with if not incarcerated.

The location of their most recent arrest.

The court address where the inmate was convicted and sentenced.

"[Inmates] have to choose where they're going to vote and fill out the registration forms accordingly. Then they're going to get a special ballot and they have to write in the name of a candidate," said Réjean Grenier, a regional media adviser with Elections Canada.

Special ballots are always scheduled before the federal election voting date, and the results are supposed to be counted in Ottawa at least five days before the election, according to Elections Canada. Unlike normal ballots, inmates have to indicate in writing the name of the candidate they would like to vote for.

Elections Canada will train a staff member at the correctional facility to handle voting day. That person is given a booklet showing all the candidates in every federal riding, and inmate voters will select a name from the appropriate riding list.

Jessica Hutchison takes Grand Valley Institution at its word and has faith voting will run smoothly there today.

As for other institutions, Hutchison thinks voting violations in prisons could be a much wider issue — particularly for maximum security inmates.

"I wouldn't be surprised to hear if there were some other institutions across Canada where this takes place," said Hutchison.