Shams Alsubaiy says she pricked her finger when she reached into the bag, bought at a Woolworths supermarket, on New Year's Day.
"When we cut it open there was a needle stuck through it," her partner Skender Hasa told 9 News.
They decided to cut open all the grapes left in the bag, and found a second needle.
"I was just shocked, scared. I thought this was all over and done with," said Mr Hasa.
Police are investigating, and Woolworths told 9 News it was working with them to find out how it happened.
