DENVER, Colo. -- Colorado's liquor stores said they are worried about legislation set for introduction this week.

Sen. Brandon Shaffer, D-Longmont, and Rep. Jack Pommer, D-Boulder, are working on a bill that would allow supermarkets to sell both regular beer and wine.

Colorado liquor store spokesman Scott Chase said that is problematic for business.

"Beer and wine make up 70 percent of the sales for liquor stores," said Chase.

Chase said there is concern that such a bill would shut down mom and pop shops.

In Littleton, the Safeway grocery store, located at 181 W. Mineral, sells wine, liquor and beer.

A provision in the law allows each chain one store in the state to operate a liquor store. Customers there said they liked the option of purchasing their beer and wine along with their milk and eggs.

"It's convenient and it just eliminates another stop," said one shopper.

That shopper sentiment is what grocers are banking on, according to grocer spokesman Sean Duffy.

"If this legislation passes, grocery stores would only be able to sell full strength beer and wine, not spirits. Liquor stores would maintain their monopoly on spirits. We think there will be a robust competition among liquor stores and among grocery stores. The customers will have a lot more choices," said Duffy.

Liquor stores will also be introducing legislation as an alternative to the bill. They are pulling for a law that would keep liquor stores open on Sundays.