"Unfortunately, there are still a large number of plastic bags being used for fruit, vegetables or bulk produce," Mrs McGrath said.
"Plastic never goes away, it takes 500 years for a standard bag to degrade.
"The issue is they go straight into our waterways, and in a city where we are known for our beautiful lakes, we don't need them polluted with all this plastic."
While most multi-use shopping bags are designed for the end of your shop, the two women wanted to create a product to replace the smaller bags used in the fresh produce section.
"To use them is really simple, you just have to refuse the plastic ones that are there at the moment."
The bags come in a variety of sizes and the larger ones can carry up to 4kg.
"People really love the idea, they have been excited and positive that there is something else they can use," Ms Fitzgerald said. "It's already got a lot of supporters."
Both women said it was great to see Countdown taking action. New World is also taking a vote on selling its plastic bags.
"There are countries like Kenya where they are already plastic bag free.
"We have such a beautiful environment. Why would we want to destroy that?" Mrs McGrath said.
Okere Falls store manager Rachael Atkinson thought Countdown's announcement was a step in the right direction.
"It will definitely take time for it to spread but it's great to see a big establishment like Countdown taking a stand against plastic."
She also praised the Bag Ladies for their reusable bag creations.
"I think what they're doing is awesome. We sell similar bags at our store too and people love them."
