A WorkSafe spokesperson said it was making initial inquiries to determine what happened, and what its next steps might be.
A police spokesperson said inquiries into the circumstances are ongoing.
The centre is owned by Napier City Council who said "our sincere condolences go out to this child's whānau".
"The Aquatic Centre staff are understandably emotionally impacted by the child's passing. We will be supporting our team who responded to the incident."
On Monday the council commenced an incident review process conducted by an external agency which specialises in these types of reviews.
The council spokesperson said the council would work alongside WorkSafe and the coroner "to ensure they have all the information they need".