The discovery has shocked the Hay River Society for the Prevention of Cruelty to Animals (SPCA), which has since been trying to discover who discarded the animals.
"We were quite appalled by the whole thing," said SPCA president Kerry Buhler. "That someone could do that to innocent puppies."
The puppies were apparently one or two-month-old Jack Russell Terrier crosses, a kind of small house dog, she says. "They would have been very easy to find homes for, if the person took the proper way around it."
The animals were discovered about three weeks ago by a person who does not wish to be identified. By the time the SPCA heard about it, the person had already found a home for the one puppy that survived. It is now doing well with its new owner.
Buhler says it is unclear if all the puppies were alive when they were left in the bag. They were discovered on the side of a railroad track, across the Mackenize Highway from the Red Rooster convenience store.
She says such incidents are very rare in Hay River, although there have been other cases of pet abandonment and mistreatment of animals.
"It's an extreme case which hopefully never happens again," she said.
There are lots of good pet owners around. Buhler stressed.
The SPCA is asking the public for help in the person(s) who abandoned the puppies in the garbage bag, so that information can be passed on to the town's bylaw officer and the RCMP.