De Kort Enterprises Pty Ltd, which operates the Swim and Survival Academy, pleaded guilty in the Ballarat County Court to failing to ensure persons other than employees were not exposed to risks to their health and safety.

The court heard that the 12-year-old girl was instructed to dive into a toddler pool with a water depth of about 1.37 metres during a swimming lesson in 2016.

The girl struck her head on the bottom and complained of a sore neck.

She was flown to the Royal Children's Hospital in Melbourne with a severe spinal injury.

WorkSafe Executive Director of Health and Safety Julie Nielsen said employers had to ensure the health and safety of everybody in the workplace.

"This is a tragic incident that has left a young girl with debilitating, life-long injuries," she said.

"Every employer must be vigilant and take every reasonably practicable step to protect workers and members of the public in the workplace."