The Ontario government unveiled a consumer incentives program on Wednesday aimed at reducing the number of plastic bags being used.

The goal is to cut plastic bag use in half over the next five years, Environment Minister Laurel Broten announced.

"So we're going to get a billion bags a year out of the system and that's a critical amount," Broten said.

The province has partnered with the Recycling Council of Ontario and grocer and retail associations to implement the consumer incentives system that includes store points redeemable for products, air miles or cash for customers who use reusable bags.

The program is voluntary, but if it doesn't work, the province could force mandatory per bag charges or even outright bans, the Toronto Star reported.

Other aspects of the system include training for store clerks to double-bag less often, fill bags with more items and stop bagging large or single items.

The incentive program originates from a pilot project in Sault Ste. Marie.

"It's not the be-all and end-all," Ontario Premier Dalton McGuinty said.

"But it's a really important thing that we can, each and every one of us, do on our own. I think one of the most important messages coming out of today's announcement is (that) we should all be asking ourselves what we are going to do. Why wouldn't we buy some reusable bags?"

Ontario's 12.6 million residents currently use 7 million plastic bags a day, which amounts to about four bags per person each week.

Many grocery stores have already tried to reduce the number of plastic bags being used by offering cloth or canvas bags or reusable bins and providing goodies to customers who use them, such as air miles.

The Recycling Council of Ontario, a non-profit organization dedicated to eliminating waste, says most plastic bags end up in landfills. The council also says most people feel the bags are littering their communities.

But if the plan is not effective within five years, council spokesperson Jo-Anne St. Godard said there is no backup plan.

"As the minister had indicated in the announcements this morning, she has a regulatory tool box that she can go to if we are unable to actually achieve our target," St. Goddard said. She added that the council feels confident the goals will be reached.

After Wednesday's announcement, opposition critics blasted the plan. Conservative critic Tim Hudak said the governing Liberals took four years to come up with a system that won't reduce the use of plastic bags.

Ontario is one of many jurisdictions around the world trying to curb the growing number of plastic bags, which take hundreds of years to break down as they are made from petroleum products.

Last month, Leaf Rapids, a small town in Manitoba, became the first municipality in Canada to ban plastic shopping bags.

In March, San Francisco became the first city in North America to ban plastic bags in grocery stores and large pharmacies.

With a report from CTV's Paul Bliss