Whanganui girl's experience with arthritis the driving force behind her decision to raise funds for Cancer Society at Relay For Life

Narketa Duncan is delicately brushing her daughter's hair in their Whanganui East home on a sunny afternoon.

It is one of the last opportunities she will have to do it before Andi-lee receives a haircut that will leave nothing behind.

Andi-lee, 10, suffers from juvenile rheumatoid arthritis and uses a low dose of medication used by some cancer patients to treat it.

She experiences some of the side effects, so knowing a bit about what they go through, Andi-lee started raising funds and is shaving her head for Cancer Society.

Carlton School student Andi-lee says she is also going to sell her locks to Freedom Hair, who make and sell wigs.

"I think there will be a little girl in the world that would want the hair more than I would," she says.

"I think when the day is nearly here, I'll be freaking out more than I am right now."

The haircut is going to happen at 12.45pm at Whanganui's Relay For Life event being held at Cooks Gardens on Saturday, March 23.

Relay For Life is a 12-hour event running from 10am to 10pm which will feature a survivors' lap of honour and plenty of fun for the kids, including face painting.

Andi-lee has wanted to shave her hair off since 2015.

"I understand that she doesn't get what her hair means to me, she doesn't care," Narketa says and then laughs.

"I kept saying no because it's really beautiful, I was letting her brother grow a rat's tail even though I didn't like it. I couldn't say no to one and yes to the other."

Funds are being raised for Andi-lee's cause through a Givealittle page, as well as a fun day in Eltham with raffles and stall holders donating half of their profits.

Carlton School teachers are donating casual Friday funds to the cause and Mad Butcher Wanganui will give $3 and $5 for every $60 and $100 meat pack sold.

Narketa is proud of her daughter who is somewhat following in her footsteps.

"I shaved my hair off for Kids With Cancer when Andi-lee was 2. Mine was down to my bum, so that probably made two wigs," Narketa says.

"Four," Andi-lee replies and they laugh together.

The two of them have given the process a bit of a test run and Andi-lee got the side of her head shaved, which she said looked cool.

Something that will be comforting to Andi-lee is the fact the she won't be the only student with no hair when she returns to Carlton after the weekend of the cut.

Nine-year-old Maddison Williams is having her head shaved on March 18 in honour of her gran who died of cancer in 2016.

Narketa says her daughter has a beautiful heart.

"She thinks of some poor little girl out there that's worse off than her, even though she struggles day to day just like they do.

"Andi-lee's really brave for doing this, but I see what she goes through, so for her, this is a piece of cake."