A 10-year-old Australian girl who survived being stung by the world's most venomous creature, the deadly box jellyfish, may have rewritten medical history, an expert says.

Schoolgirl Rachael Shardlow lost consciousness after being badly stung by the jellyfish while swimming in a river in Queensland with her brother in December, but lived to tell the tale.

Raechel Shardlow ... survived multiple stings from a deadly box jellyfish. Credit:ABC TV

"When I first saw the pictures of the injuries I just went: 'You know to be honest, this kid should not be alive,'" said Jamie Seymour, professor of zoology and tropical ecology at James Cook University.

"I mean they are horrific. Usually when you see people who have been stung by box jellyfish with that number of the tentacle contacts on their body, it's usually in a morgue," he told the ABC.