"It is for customers who get caught out with a load of groceries and have forgotten to bring their own bags."
Kiri says the bag is made from 55 micron plastic and designed to be used up to 20 times.
Any profits from the sale of the bags would be donated.
She says the company would review the bag over the next year to decide if it was still needed.
Countdown's priority was for people to bring their own bags or buy Countdown's $1 reusable fabric bag.
Te Awamutu Countdown will be one of 87 Countdown stores across the country to ban the bag so far, with the rest joining before the end of 2018.
Signs have been set up at the entrance of the supermarket and the checkouts to warn customers of the change.
The ban means 5.2 million single-use plastic bags will be removed from circulation every week nationwide.
Cambridge Countdown is still using plastic bags. However, customers are encouraged to get into the habbit of using reusable bags.
Countdown's initiative comes after the Government announced plans for a mandatory phase out of single-use plastic bags over the next year.
Kiri says Countdown was "proud to be doing our bit for the environment".
"We're really pleased to be helping get Kiwis ready for a wider national phase out by helping to make reusable bags the norm.
"While we have a long way to go, this is just the beginning for us."
Over the last year Countdown has removed more than 70 tonnes of unnecessary plastic from its produce section, including removing plastic packaging from bananas — this alone removed 15.8 tonnes of plastic.
Countdown also said it would remove single-use plastic straws by October 1.
It would also use new packaging for dozens of its in-store bakery and delicatessen products.
The new packaging is locally-sourced recycled PET (rPET) packaging.
The name rPET stands for recycled polyethylene terephtalate and is plastic that has already been used for packaging, such as plastic bottles.
The products packed with rPET will be in store from October.
