A 20-year-old woman was arrested in the store and is being interviewed by detectives.
One shopper said he saw the incident, which he claimed occurred in the bakery section.
"I heard a scream and there was a lady that got stabbed by ... it looked like a person working in the same department," he told 3AW radio.
"I heard the screams and went over and checked it out and saw the staff members come over.
"I saw them carry the knife away as well."
This story first appeared on 7NEWS.com.au