Toronto's former city hall will likely serve as a courthouse for an additional five years as city council considers extending the province's lease until a new downtown facility is built.

A report presented to the city's government management committee earlier this week recommends stretching the lease to Dec. 31, 2021.

City council is expected to approve the extension at its Nov. 3 meeting. The move would include a rent increase of nearly $43,000 per year.

What to do with the building -- which was designated a national historic site in 1984 -- once the courts move out is also up for consideration.

The report suggested the "best use" for the building once its current tenants move out would be "a retail centre that contains a mix of food service, leisure, event and civic uses."

But the committee voted to study the possibility of turning the site into a museum chronicling the city's history before looking into other tenant options.

Coun. Josh Matlow was among those opposed to the prospect of converting the building into a mall.

"Suggesting that this significant part of Toronto's history become another shopping mall is selling our city short. Home decor and beauty stores are hardly appropriate future uses for this space, in light of the important civic functions performed here over more than a century," he wrote in a letter to the committee.

The lease is currently set to expire on Dec. 31, 2016.

The Ministry of the Attorney General said it requested a seven-year extension "at fair market value" because it will need the space until the opening of the new Toronto courthouse.

Construction on the publicly owned courthouse is set to begin in 2017, a spokeswoman said.

"However, it is difficult for us to commit to start and completion dates before a construction company has been selected, as this company will include a schedule with its bid submission," Emilie Smith said in an email.

A request for proposals to select an architectural firm was issued in July.

The new facility will be located near Old City Hall on provincially owned land.