Marnie (13) and Lucy (11) have been touched by cancer twice during their young lives, losing their grandfather and a close family friend to the disease.

"I decided to cut my hair because a couple of years ago a friend passed away because of cancer," Marnie said.

"She lost her hair through chemo and she got a wig so I thought people like her might need more wigs."

Lucy remembers wanting to cut her hair since she was five.

"When I was in Kindergarten my Poppy died of cancer and ever since then I've wanted to cut my hair and raise money," she said.

And raise money they have - a whopping $2,244 so far for the Leukaemia Foundation, with donation tins still to be collected.

The big chop was planned to take place during assembly at Parkes Christian School on Friday morning.

The girls popped into see Kara Timmins, at her salon Hair with Kara Jane, on their way to school so she could place bands where it was to be cut.

Principal Glen Westcott and Central West Kyokushin Karate Sensei Michell Kable had the honour.

"I chose Mr Westcott because I respect him and he likes to do fun stuff," Marnie said.

Lucy said she chose Michelle because througout her time learning karate she has taught her to find courage, confidence and strength.

"I knew I would need to use all those things when my hair was cut," she said.

After school the girls went back to the salon to have their hair styled by Kara.

Marnie's hair measured 27cm and Lucy, who has only ever had her ends trimmed, was able to donate an impressive 70cm.

Lucy likes her new style but said she thinks she still likes long hair better.

"I'm definitely going to start growing it immediately," she said.

Despite the girls wanting to donate their hair for quite some time, their parents wanted them to be a little older before allowing them to do it.

"Mark and I wanted to make sure they understood the real reasons behind it," Liz said.

"The school showed a video at assembly which explained what leukaemia is and what Shave For A Cure is about."