The Ontario government is standing alongside a Mississauga, Ont., woman who is challenging the federal government's ban on face-coverings at citizenship ceremonies.

It has filed its position, called a factum, with the Federal Court of Appeal in advance of a hearing scheduled to begin next week in Ottawa.

The province argues that requiring a Muslim woman to remove her niqab during the public oath-taking ceremony "with the result that if she does not she cannot become a Canadian citizen, fails to respect and accommodate the diversity of religious beliefs and socio-cultural backgrounds of Canadians."

The factum goes on to say the government's policy "tells Muslim women that if they wear the niqab, they are not welcome to join the Canadian community."

The province is also of the view that "visual inspection of a person's face does not prove that the person has actually spoken the words of the oath or affirmation. The proof is already provided by the existing requirement that citizenship candidates sign a certificate certifying they have taken the oath or affirmation."

Next Tuesday, lawyers for the minister of citizenship and immigration will try to persuade the Federal Court of Appeal to reinstate the ban after it was struck down last February.

Justice Keith Boswell ruled the government's new citizenship policy on face coverings is unlawful.

The case started with a lawsuit from Zunera Ishaq, a devout Muslim who moved to Ontario from Pakistan in 2008 to join her husband. Ishaq agreed to remove her niqab for an official before writing and passing her citizenship test two years ago, but she objects to unveiling in a public citizenship ceremony.

Boswell ruled the federal government policy violated the Citizenship Act, which states that citizenship judges must allow the greatest possible religious freedom when administering the oath. Boswell asked how that would be possible, "If the policy requires candidates to violate or renounce a basic tenet of their religion."

Within days of the decision, Prime Minister Stephen Harper announced the government would appeal the judgment and said he and most Canadians believe "it is offensive that someone would hide their identify at the very moment where they are committing to join the Canadian family."

In its notice of appeal, lawyers for the federal government argued Boswell committed several errors in fact and law.

Despite the pending appeal court hearing, the government tabled bill C-75, the Oath of Citizenship Act, as one of its last acts before Parliament rose for the summer in June. The proposed legislation would again seek to enshrine in law that one's face must be uncovered to take the oath of citizenship.