Government sources say Premier Kathleen Wynne will announce plans Thursday to match federal riding boundary changes, except in northern Ontario where the Liberals want to maintain one additional provincial seat.
The Liberals say they want to make sure the "unique needs of the north" are protected with one more elected provincial representative than at the federal level.
The number of Ontario ridings — and MPPs — will grow from 107 to 122, while federally there will be 121 ridings in the province.
The federal Electoral Boundaries Commission made changes to the boundaries of many ridings and created 15 new electoral districts in Kitchener, Hamilton, Halton, Brampton, Mississauga, Simcoe, York, Toronto, Ottawa, Belleville and Durham.
Ontario's riding districts have closely matched federal ridings since 1999 when the previous Tory government reduced the number of MPPs from 130 to 103, but Ontario added one additional northern riding in 2005.
The increase in the number of Ontario MPPs will be part of a package of electoral reforms Wynne is expected to announce.
The Liberals promised in the budget to strengthen rules around third party advertising during campaigns after Elections Ontario reported spending by non-political parties more than tripled since the 2007 election.
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