It is the first time Otago has entered a contestant in the pageant in 12 years and the 22-year-old Queenstown beauty therapist said it felt "great" to represent not just the region, but the entire South Island in the event.
Asked how confident she was of placing in the prestigious pageant, Miss Cooley said it was "unpredictable".
"People grow through the week ... the girls get more confident every day.
"Our interviews with the judges are important, but they're private so you don't know how anyone else goes. It all counts."
Ten women are in the running to be crowned Miss Universe New Zealand - nine of them from the North Island.
Five will be placed in the event, the overall title and four runners-up.
Additionally, there are awards for Miss Charity Queen, Miss Personality, Miss Swimwear, Miss Friendship, Miss Photogenic, the Beautiful Hair Award and the Evening Gown Award.
Miss Cooley was crowned Miss Otago in October and has since been juggling work commitments and preparation, which included regular gym workouts at Queenstown Gym.
She arrived in Wellington on Sunday and had barely been able to catch her breath since.
The contestants have started each morning with rehearsals before official visits to Parliament House, rest-homes and Te Papa, as well as meeting the deputy mayor of Wellington, Ian McKinnon.
On Thursday afternoon they spent the afternoon "spritzing" perfume at a Lambton Quay department store and appearances yesterday included a parade at Johnsonville Mall.
Miss Cooley said she would have support in the audience on Sunday night from her mother, Linda, partner Andrew Wylie, and her best friend, who was flying over from Melbourne for the final.
"I am a wee bit nervous, but it's a competition, so I think nerves are healthy.
"You're so full-on all day you don't really have time to think about the nerves until you go to bed."
