The 12-year-old Kooringal High School student is planning to donate her hair as part of the World's Greatest Shave in memory of family friend Shannon McKnight, who died at the age of 19 from acute lymphoblastic leukaemia.

Diagnosed when she was just 17, Shannon fought the illness for two years. She died in 2016.

Shannon's mum Jodie Wilesmith said her daughter had been very important to her young friend Macey.

"We used to hang out quite a bit," Ms Wilesmith said.

When Shannon was undergoing chemotherapy treatment, she lost all of her hair and Macey had desperately wanted to donate her own to be made into a wig for her friend.

"But it just wasn't long enough then," Macey said.

Instead of giving her hair to Shannon, Macey will be donating it in memory of the former Wagga High School student.

Macey admits she is nervous about having her hair cut to shorter than shoulder-length, but also excited and happy that she is able to make the donation.

Macey will be losing her locks - or at least part of them - on March 16 outside Blooms pharmacy in the Wagga Marketplace.

Ms Wilesmith said Wagga retailers had thrown their support behind Macey, so there will be raffles and fun, including the chance for children to have their own hair sprayed in vivid colours.

Macey has exceeded the $500 fundraising goal she set and now hopes to raise $1000. To help, go to the website.