The Ontario Convenience Stores Association began legal action against the city on Thursday, saying the proposed ban was approved without a proper consultation process.
Toronto city council must still approve the ban, which is to take effect on Jan. 1, 2013, after the city's public works and infrastructure committee adopted the proposed bylaw on Wednesday.
Association spokesman Dave Bryans calls the proposed bylaw "invalid" and says it was rushed forward with essentially no consultation with the businesses it will harm.
Bryans says the ability to provide consumers with reliable, strong and cost-effective bags to carry their purchases home is a vital part of convenience stores' ability to meet consumer demand.
The Toronto Taxpayers Coalition says it also plans to proceed with a legal challenge.