Kellogg's has changed its Nutri-Grain packaging after an 8-year-old girl challenged them over their "sexist branding".

Daliah Lee wrote to the cereal giant in May calling them out for only featuring boys on the box, writing "girls could also do something awesome" as well.

She told Kellogg's its packaging was sexist and asked it to make change.

Daliah's mum explained her daughter first noticed the questionable packaging when she sat down to eat Nutri-Grain one morning.

"One morning earlier this year Daliah was eating breakfast of Kellogg's Nutri Grain and noticed that only boys were pictured on the box doing extreme sports. Not a girl in sight," Ms Lee wrote on Facebook.

"She asked me what was happening and grabbed at the opportunity to write to Kellogg's herself and ask them to fix it."

In the letter dated May 10, Daliah, from Canberra, asked: "Why can't girls be on the back?

"Can this please stop it's not fair. Girls can do something awesome too.

"I'm happy because the Weet-Bix brand puts girls on the front and the back of the box. Please fix this."

Kellogg's initially responded to Daliah's letter saying her views would be "forwarded on to our product development team".

However, the young girl was disheartened, calling the company's response "kind of blah, blah, blah" so she started a petition on Change.org.

On Friday, Daliah's hard work paid off when Kellogg's announced it would include women on their Nutri-Grain packaging.

"Hearing Daliah's passion and, as a company that values diversity and inclusion, we've decided that we will update the back-of-pack imagery with images of both females and males," the company said in a statement.

"This will be rolled out in 2019, so that we can continue to inspire all Aussies no matter their gender."

Following the news, Daliah was ecstatic and can't wait to see the new packaging.

"I jumped up and down and screamed, I was so excited," she said.

"Finally all my hard work has paid off. Children are important as well and need to be listened to."