Speaking to Yahoo7 News, Kirsty McDonald said that she had purchased standing tickets to Sheeran’s sold out show, not thinking she would need to buy an extra ticket for her son, Leni.
"This, in my eyes, is simply being money hungry," she told Yahoo7 News.
"The promoter should have made tickets for infants, like airlines do," she added.
"In this day and age people take their children along to any number of events that prove to be noisy," she said.
"Would I be shamed for taking him to the local school fete to watch fireworks? I don't think so."
After contacting Ticketek about her son, she was told via email it was not possible to bring him for "free on the knee" and that she would need to buy a ticket for Leni.
Meanwhile a spokesperson for Frontier Touring, the event promoter, says it came down to safety.
"Part of the reason that we require people to have a ticket is knowing exactly how many people are in the venue, which is primarily for a safety reason," a spokeswoman said.
This article originally appeared on New Idea.