"The only cosmetic procedure I had was my breasts 10 years ago," she told Daily Mail. "I don't use Botox or fillers as I believe in ageing gracefully."
She added: "But seriously, there's no secret. I think everyone is beautiful. I'm not doing this for attention as I hate it. I'm just trying to make a difference to inspire women not to rip each other apart."
Gina took part in the competition in the hope she would win and be able to donate the $10,000 prize money to her friend who recently had a stroke.
"I'm only hoping to win to help my best friend of 30 years as she's had a stroke," Gina said.
"If I win Maxim, I would be donating to her to help with her recovery. I'm just hoping to raise awareness for stroke victims."
On her Maxim profile, Gina says she is best known for her sense of humour, "how much I care about people, friends and family. Also my laugh and Instagram videos"
The Daily Mail reported that Stewart is believed to be the sister of Underbelly star and New-Zealand born Logie award winning actor Aaron Jeffrey.
She said she is inspired by "people who do what they say they are going to do. People who still have the strength to keep going and be positive even after going through hard times. People that never give up really I find the most inspirational.
When asked if she could rule the world for a day, she would: "Make it so that Chocolate, Peanut Butter and Nutella would all have zero calories."
The next stage of the Maxim Australia competition is on Tuesday.