A group of Canadian republicans, some of whom are Irish, are refusing Canadian citizenship and suing because the ceremony involves swearing an oath to Queen Elizabeth.

Instead, according to the Globe and Mail, the group will be in a Toronto courtroom on Friday in a high profile showdown with the federal government to have the citizenship requirement of an oath to the queen declared unconstitutional.

Among the prospective citizens now suing is Michael McAteer, 79, a long-time anti Monarchist who grew up in Ireland but has lived in Canada since 1964. He has never been able to become a citizen because of his refusal to swear the oath.

McAteer, a former journalist at the Toronto Star, calls the monarchy an anachronistic institution ill-suited to Canada’s multicultural society.

'I obey the law. I’ve probably seen more of Canada than most Canadians. I’ve shovelled my sidewalk, and you know, paid taxes,' he said. 'I feel very comfortable here, in Canada. But still, after all that, I still cannot become a Canadian citizen.'

Canadian Prime Minister Stephen Harper has recently dedicated his administration to reviving the country's connection to the monarchy, so the republican group may have quite a fight on their hands.

The government is expected to argue that immigrants who disagree with the idea of a hereditary head of state, and refuse to swear an oath of loyalty to the Queen, simply do not deserve the benefits of citizenship.

'The inability to enjoy the benefits of citizenship – to hold a Canadian passport and to vote – are amongst the costs reasonably borne by individuals whose personal beliefs run contrary to Canada’s foundational constitutional structure,' a lawyer for the federal Attorney-General says in the written arguments submitted before Friday’s hearing.

But the Toronto lawyer for the group fighting the oath, Peter Rosenthal, said that position was surprising: 'The Attorney-General has taken the position that if you don’t believe in the monarchy, it’s appropriate to deny you the right to vote. That’s pretty extraordinary, given the fact that more than half of Canadians don’t believe in the monarchy.'

Friday's court fight is not the first of its kind. In fact it's just the latest chapter in more than 20 years of failed legal challenges to the Canadian citizenship oath led by Trinidadian-born Toronto activist and lawyer Charles Roach, who died last year at 79, never having become a Canadian citizen.

Roach, a long-time friend of Rosenthal's, refused to swear the oath and become a citizen because he believed the Queen was a symbol of imperialism and because of injustices done to his ancestors in the name of the British monarchy.

The court case has been taken by the group that want the part of the Canadian oath that refers to swearing allegiance to 'Queen Elizabeth the Second, Queen of Canada, her Heirs and Successors' struck down because it violates the protections for freedom of religion and conscience in the Charter of Rights and Freedoms.

A spokeswoman for the Ministry of Citizenship and Immigration told the Globe and Mail that the government had no plans to change the oath.

'Canadian citizenship is an honour and a privilege,' spokeswoman Sonia Lesage said. 'The government has been working hard to maintain the integrity of the system and to increase the value of Canadian citizenship.'