PORTLAND — A proposal by the city of Portland to charge shoppers for disposable plastic or paper shopping bags has moved forward after a city council committee voted to lower the proposed fee and send it to the full council.

The Transportation, Sustainability and Energy Committee voted 3-1 Wednesday to slice the per-bag fee from a dime to a nickel.

Supporters say charging for bags would cut down on litter.

The fee would apply at stores where food constitutes at least 2 percent of gross sales but would not apply to dry cleaners, restaurants and farmers’ markets.

If enacted, Portland would become the first municipality in Maine to impose such a fee.

Opponents, including businesses, say the fee is a tax and the problem lies with the people who improperly dispose of bags.