Toronto's city clerk signed off on holding a byelection in one of the city's northernmost municipal ridings on Friday, after a Superior Court Justice said there were irregularities with the voters list.

City clerk Ulli Watkiss said that the city would not appeal the decision to recast Toronto's Ward 9, after a judge determined the October election results were invalid.

Ward 9 (York Centre) voters will return to the polls on July 25.

"The decision to proceed with a byelection and resolve this matter as quickly as possible is in the best interest of the public, the individuals directly affected, and the workings of Council," Watkiss said in a statement.

The byelection is expected to be a rematch between incumbent Maria Augimeri and her Rob Ford-supported rival Gus Cusimano.

Augimeri had held onto her seat in Ward 9 (York Centre) by beating Cusimano by just 89 votes in the Oct. 25, 2010, municipal vote.

Toronto District School Board Ward 4, represented by trustee Stephnie Payne, will also hold a by-election, Watkiss said Friday.