The incident at Roundhill campsite near Brockenhurst is understood to have happened over the weekend, sparking fresh warnings not to approach or touch free-roaming animals.
Andrew Parry-Norton, of the New Forest Commoners Defence Association, said he was saddened by the incident and sympathised with the child and their family.
He said: “We don’t want this to happen to anybody.”
Mr Parry-Norton said people must keep a safe distance from New Forest ponies.
He said the association were not being “killjoys” or awkward by asking visitors to avoid going close to or touching the ponies.
He added: “It is an appalling thing to happen to anybody and it is something we have to think about, which we are doing.
“We have got to try and get this message out somehow better than what we are doing.
He said: “Our deepest sympathy to the family.”
Thousands of free-roaming ponies live in the New Forest, and visitors are warned not to approach, feed or attempt to pet the animals because startled or threatened animals can react unpredictably.
Hampshire Police said two children had been kicked by ponies in the New Forest during the summer of 2025.
