OTTAWA — The Canada Plastic Bag Association on Tuesday joined a growing number of groups suing Toronto, Canada's largest city, to stop a proposed ban on plastic shopping bags.

The association said its members "have a substantial economic interest in the manufacture, supply, distribution and sale of plastic bags in Toronto and would, wholly and individually, be significantly impacted by the plastic bag ban."

It and other critics say the ban was approved on the fly without public consultations or study by municipal officials.

Council passed a surprise motion to ban plastic shopping bags in June after Toronto's mayor asked to get rid of a five cent charge for bags.

The Ontario Convenience Stores Association last week announced a legal challenge. The Toronto Taxpayers Coalition also said it would try to stop the ban, which goes to council for final approval November 27.

Proponents of the ban say the ubiquitous plastic shopping bag is a blight on the environment, polluting waterways and killing animals.

Leaf Rapids, Manitoba was the first town in the western world to ban plastic shopping bags. Its town council passed the bylaw on March, 22, 2007, five days before San Francisco, the first in the United States, and one month before Modbury, England, the first in Europe.

Toronto would the first major Canadian city to ban plastic bags when its bylaw takes effect January 1.

The bylaw however would still allow plastic bags to be used for bulk food items, frozen foods, meat or fish, flowers, potted plants, prepared foods, bakery goods, prescription drugs, newspapers, and dry cleaning.

Bags for garbage and picking up curbside pet poop also could still be purchased in stores.