Four weeks after it started charging a five-cent fee for single-use plastic bags, the Metro grocery store said Monday its customers in Ontario and Quebec are using 70 per cent fewer bags than the normal monthly average.

The grocery store enacted the new fees across Ontario and Quebec on June 1.

Metro also reported Monday that sales of reusable bags had gone up by five times since the fee was implemented.

Metro isn't the only major grocery store to be charging for the use of disposable plastic bags. Loblaws and Sobeys have also instituted a five-cent charge, although Sobeys only charges the fee in Ontario.

Loblaws has reported that 75 per cent fewer plastic bags than normal have been used since it started charging fees nationwide on April 22.

The City of Toronto has also mandated a five-cent fee for plastic bags at retail stores in an effort to cut down landfill volumes. The city has said it wants to reduce plastic bag use by 70 per cent by 2012. The retailers get to keep the nickel under the Toronto law.