"This is a really tragic, and unexpected occurrence which saddens us all," he said. "Our thoughts go to the family involved."
He was not yet aware of the details of the incident, but said it sounded as though the young boy had been pulled from the Waikoko Lake, in the gardens at the front of the showgrounds.
This lake varied in depth from half a metre, to four metres and was not fenced, he said.
There had been no scheduled public events at the showgrounds this afternoon. As the Waikoko Gardens were accessible to the public, Mr Linn said he thought the group with the toddler must have gone to the gardens for an afternoon outing.
He said he was not aware of any incidents like this ever happening at the showgrounds before.
"I only feel for the parents, as a parent myself I [understand] the trauma and concern they must be going through," he said.
"I'd like to talk to the family and pass on our support and concern that this has happened."
For the showground staff, he said it was a "balancing act between providing public access to the showgrounds and relying on people to self-manage that risk."