Despite moving ahead with its own plan to elect senators, the New Brunswick government is arguing the federal government can’t reform the Upper Chamber on its own.

In a factum filed Friday at the Supreme Court of Canada, the province’s attorney general argues most of Ottawa’s ideas require the approval of seven provinces representing more than 50 per cent of the population — one of the amending formulas for the Constitution.

But on the question of whether Ottawa could abolish the Senate altogether, New Brunswick is arguing that would go against the 1867 agreement on Confederation and would require the unanimous agreement of all provinces.

"To require anything less than unanimous consent would undermine Canada’s constitutional foundation including the terms upon which New Brunswick and the other provinces and territories agreed to enter into Confederation," reads the 53-page brief.

The factum was filed as part of the Harper government’s reference case to the Supreme Court. Ottawa has asked the court to rule on the constitutionality of various options for Senate reform.

The top court will hold three days of hearings in the case in November. In the brief, the New Brunswick attorney general requests permission to appear at the hearings to make oral arguments.

Among the factum’s arguments:

On whether Ottawa can create term limits for senators, New Brunswick says no. The factum argues term limits would threaten the Senate’s constitutional role established in 1867, which means they can only be established with the consent of seven provinces representing more than 50 per cent of the population.

On whether Ottawa can hold federal elections for senators, or pass a law requiring the provinces to hold its own Senate elections, New Brunswick says no. The factum argues this would also require the 7/50 formula.

On whether Ottawa can eliminate the property qualifications for Senate appointees, which require they own $4,000 in land or property, New Brunswick says yes. The province argues this doesn’t change "the essential character" of the Senate so it doesn’t require a constitutional amendment.

New Brunswick said its own legislation to elect senators doesn’t require changes to the Constitution.

The New Brunswick bill would see the province hold elections and submit the names of the winners to the prime minister for appointment.

The New Brunswick factum argues because that process is not legally binding on Ottawa and doesn’t affect other provinces, its bill does not affect the Constitution.

Premier David Alward's Progressive-Conservative government has put a hold on its consultation process for its Senate election bill until the Supreme Court rules in the reference case.

It’s estimated that a ruling could come 10 to 24 months after the hearing.

Newfoundland and Labrador and Nunavut, which filed their submissions Thursday, take similar positions.