Ontario's highest court is considering the thorny issue of whether a sexual assault complainant should remove her niqab to face her alleged attackers in court.

The issue has drawn attention from several groups, that are not only split on whether or not a woman should be able to wear a veil in the witness box, but also on the fundamental questions the issue evokes.

Lawyers for no fewer than seven parties were making submissions starting Tuesday before the Court of Appeal for Ontario.

Some argue it is about Charter rights such as freedom of religion and fair trial rights, while others say it is about the revictimization of alleged rape victims, and then there are those who say it is about what the niqab represents to all women.

The case began in 2007 when a woman, now 32 and identified only as N.S., told police that her cousin and uncle repeatedly sexually abused her while she was between the ages of six and 10.

During the preliminary inquiry, which is held to see if there is enough evidence to go to trial, the judge ordered N.S. to remove her veil to testify. After going through the Superior Court, the case has now ended up at the Appeal Court.

A lawyer for one of the defendants said N.S. has not said she refuses to testify without her face covered, just that she would feel more comfortable wearing the niqab.

Without being able to view the face of a witness, clues to her demeanour are lost and impede the defendants' ability to fully cross-examine her, Michael Dineen said.

He gave an example of a teenage witness in a recent murder trial who changed her story on the stand after a defence lawyer questioned her about smirking after giving an answer.

But since her eyes are visible, what's being lost in terms of demeanour pales in comparison to forcing N.S. to go against her religious beliefs, her lawyer argued.

"All you're deprived of ... is a small subset of cues," David Butt told the three-judge panel.

Demeanour evidence is inherently fallible, said a lawyer for the Ontario Human Rights Commission.

"You may have people with disabilities whose facial expressions may be affected by their disabilities," Prabhu Rajan said outside court.

"In effect what you're suggesting as well [is] you can't have blind judges or blind lawyers because obviously a blind judge or a blind lawyer is not able to view facial demeanour."

The Women's Legal Education and Action Fund takes the position that forcing N.S. to remove her veil will deter other niqab-wearing women from accessing the justice system.

"From the perspective of the complainant, the forced removal of her niqab as a pre-requisite to testifying in a sexual assault prosecution turns the metaphor of re-victimization at trial into a literal reality," lawyer Susan Chapman writes in court documents.

"Denying women access to the criminal justice system unless and until they remove their niqab constitutes a profound violation of their rights."

The Muslim Canadian Congress wants to see N.S. testify without her veil because the group says it is a political symbol of oppression of women.

"Why are we indulging in making a fool of the Canadian judicial system and values of gender equality?" congress founder Tarek Fatah said outside court.

She has already demonstrated her willingness to show her face to police officers, customs officials and has a driver's licence, he said.

The Crown suggests the court shouldn't be determining admissibility of veiled testimony, but instead a legal test needs to be created for such issues.

Whatever is decided about the niqab, if N.S. testifies at the preliminary inquiry, it is still unclear what would happen at trial.

The lower court judge said evidence given by N.S. while wearing her niqab could be excluded if it was found that it denied the accused their rights to full cross-examination.

That puts the woman in a terrible position, the Ontario Human Rights Commission says. Either she can wear her niqab and risk her testimony being excluded and the charges being dropped, or she can violate her own religious beliefs and remove the niqab to ensure her testimony is allowed.

The Canadian Civil Liberties Association also takes the position N.S. should be allowed to testify wearing her veil.