Doctors are calling for warning signs at aquatic centres to prevent girls and women suffering internal injury from high-speed water.
A paper published in the New Zealand Medical Journal today reports on two cases of "vaginal water-jet injuries" in pre-adolescent girls.
In one case an 8-year-old suffered abdominal discomfort, an
internal cut and heavy vaginal bleeding within minutes of playing on a high-pressure fountain.
In the second case, a 10-year-old experienced similar problems after sliding feet first down a hydroslide.
Both girls had been wearing one-piece swimsuits.
The report said the cases were uncommon but potentially serious.
"It is important for medical personnel to be aware that major vaginal injury may result from seemingly innocent watersport activities," the report said.
"Warning signs at aquatic centres and the use of wetsuits when participating in high-speed watersports could be considered as preventive measures."
Garry Dunn, general manager of Aquatic Park Parakai Springs, was not aware of any such injuries at the Auckland centre, but said it was unlikely young girls would tell staff.
The centre, which had two water slides, had signs advising people to go front first down the waterslide.
He questioned how effective the signage suggested by the doctors would be, what it would say and how many people would read it.
Mr Dunn said it would perhaps be more effective for mothers to make their daughters aware of the problem.