TORONTO - NDP Leader Andrea Horwath says Ontario's plan to merge sales taxes will mean a seven per cent increase in costs for condo owners in the province.

Horwath says the although the harmonized sales tax does not apply directly to condo fees, it will increase expenses such as hydro, landscaping, repairs and maintenance.

That would mean an increase of about $28 a month for people who pay monthly condo fees of $400.

Horwath wants the government to stop the tax changes, saying now is the wrong time to make housing less affordable.

Premier Dalton McGuinty has given no sign he's willing to back away from the controversial tax change, calling it one of his government's most important policies.

There are over 350,000 condo units in Ontario.