She said after her daughter was rejected from one ride in front of her friends.
Another mum said her daughter experienced "public humiliation and body shaming" despite meeting the weight limit.
"She even mentioned the anxious wait on the scales for the red light or green light. Not a nice way to feel and could be detrimental to mental health for some."
Another person acknowledged it wasn't the weight requirement that had caused fury. Instead, it was how it was being enforced.
Others accused the operators of being indiscreet and revealing guests' weight in earshot of others in the queue.
An Adventure World spokesperson responded to online complaints by clarifying that on many rides those over the weight limit could ride, as long as they fit in their harness and the total weight of all riders didn't exceed the maximum.
In a statement to The West Australian newspaper, Adventure World chief executive officer Andrew Sharry said: "We take our direction from our various ride manufacturer's safety specifications."
"There have been no changes to, nor introduction this season of a new rider weight safety requirements for any of our rides, slides or attractions," he said.
The CEO said the weight scales were for the comfort of patrons, as well as a "rider weight safety assessment scale for the operator".
"[This] brings us in line with almost all other water parks in the country. We are not alone in implementing such a system."