This year, the pageant has again opened the category to budding designers and the competition has been narrowed down to four choices.
"It's so easy for us to jump on them, and say they're not this and they're not that, but I would like to question everyone about what they do in place of it," Ms Busteed said.
"The national costume is always such a difficult thing for Australia to do, and all the countries."
Now based in Brisbane, Ms Busteed received flack for her lifesaver outfit in 2007, which some described as frumpy.
"I loved it, absolutely loved it," she said. "It was back in the days when it wasn't up to designers to choose. We just got told what to wear.
"I thought it showed off Australia well and me as well. It presented the girl that I am."
Designer of this year's Great Barrier Reef-inspired gown Jason Chetcuti, who also won his first fashion competition in Gladstone about 15 years ago, said the costume section was all about fun.
"I think it's excellent and fantastic," he said.
"I think the best part of it is getting the feedback. You can gauge what the public of Australia think about your work."
Previous costume choices that have received negative feedback include Erin McNaught's outback shirt and shorts ensemble in 2006 and Jesinta Campbell's 2010 high heeled ugg boot look.
Ms Busteed, who is a lifestyle presenter for Channel 7, said people should back off the negativity and show their support.
"When it comes down to it, Olivia is going to be proud and happy in whatever she gets to wear and she's going to wear it with pride," she said.
"It's just a shame she has to deal with all of this crap, instead of people giving her a pat on the back."
The costume winner will be announced on September 20, with the Miss Universe pageant being held in Moscow on November 9.
For more visit missuniverseaustralia.com.au.