It has been a fairly quick rise in the sport for the personal trainer after taking up the code in 2011.
She said she got into it to set an example for her clients.
"When I qualified as a personal trainer in 2011 I felt the best way for me to help others achieve their health and fitness goals was to throw myself in the deep end and get first-hand experience," she said.
"Plus I already had an advantage with my 'horse rider legs'. I represented Northland with equestrian and still ride to this day."
Barker has started up a Givealittle page to fundraise the $7000 in costs to get to Las Vegas for the event, which runs from November 9-12.
She said she would not get to compete at these events without some help.
"If it wasn't for my sponsors I wouldn't have made it to Queenstown. They were Brenda's Beauty Bar Waipapa, BP Kaeo, Hardy's Health Store Kerikeri and Champion Nutrition Auckland."
While she has competed on the world stage before, Barker feels she has a more realistic chance for success in a now clean competition.
"I've competed in Germany and Spain but I've learnt that was unrealistic for me because I was always pipped at the post by drug," she said.
"Natural Olympia is exciting because I'm up against a fair competition."
"I'm nervous but excited. I just don't want to let my sponsors down. I'm pretty confident on stage. It's all down to the training and the diet over the next four weeks."
Her goal is to come home with a podium finish under her belt.
"I've found my groove in an all-natural bodybuilding association. This time when I go overseas I know I won't get beaten by drugs."
Her training regime will now amp up in the lead-up to the competition.
"The training is intense but the diet is the hardest thing I've ever done," she said.
"Leading into Natural Olympia I will do five fasted morning sprint sessions and five one-hour walks in the afternoon during the week.
"Kerikeri will probably see me quite often with my big headphones and my pup May.
"I don't lift too many weights because I have such great genetics that I'm very blessed with. I will do a couple of shoulder sessions just to create shape and symmetry once or twice a week.
"I really thrive off being in the trenches. It's so challenging. I love the discipline and I apply it to my daily life and personal goals."