Around 6.30pm a Hawke's Bay District Health Board spokeswoman said the boy's condition was now stable, and he would be recovering in hospital.
As of last night, the details surrounding the incident are not yet known.
Yesterday Showgrounds general manager Brent Linn 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 in places and was not fenced, he said.
There had been no scheduled public events at the showgrounds yesterday afternoon - the weekly Sunday Farmers Market at the showgrounds had finished well before the incident.
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.
While the incident was "tragic", he said for the showgrounds staff it was a "balancing act between providing public access to the showgrounds and relying on people to self-manage that risk."
He said all showgrounds staff were extremely saddened by the incident, and were hoping for the best outcome for the toddler.
"This is a really tragic, and unexpected occurrence which saddens us all," he said. "Our thoughts go to the family involved."
He said he was not aware of any similar incidents 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."