Seven months after Harris Farm Markets stopped giving away plastic bags, the state's landfills and the waterways have already been spared 15 million of the waste items from their 25 outlets alone.

The family-owned company was surprised Coles cited consumer reaction to a voluntary phase-out of single-use bags at its supermarkets to start giving them away again last week. It was less surprised at the bigger rival's backflip just a day later to reset a phase-out date.

Angus Harris with his sons Hunter and Theodore at Harris Farm in Drummoyne. Credit:Cole Bennetts

"We definitely did not notice a drop in our customers since we brought [the bag plan] in," Angus Harris, co-chief executive of Harris Farm Markets, told The Sun-Herald.

Coles now plans to hand out free bags until August 29, with managing director John Durkan telling staff the company wants to ‘‘do the right thing’’ by customers struggling to adapt.