To train, Moffitt has been working out at the gym, doing Pilates and training at the climbing wall. She doesn't have a coach, but her mother Gail Moffitt belays her and acts as her main motivator.
"She puts a lot of work and time to help me progress in my sport which is really, really cool," said Sian. "I'm thankful for that. And she helps me know what I need to be doing and keeps me focused on my goals."
The four-day World Youth Rock Climbing Championships will have two days of qualifying climbs, followed by semifinals and finals.
Moffitt's aim is to beat her placing at the last World Youth Rock Climbing Championships in Singapore in 2012, where she came 35th out of 48 climbers; and make it as far as the semifinals, if possible.
Grigsby, 17, and Lockwood, 16, are both from John Paul College.
They have been spending a lot of time at The Wall in preparation.
Grigsby said she hoped to make the semifinals in the under-21 category, which means she would have to finish in the top 26 in qualifying.
She said the goal was to climb as high as possible. She added that you only get one shot to qualify for the semifinals, so it would be high pressure in Noumea.