"Despite the best efforts of our paramedics and those on the scene, the patient did not survive," AV acting Loddon Mallee regional director Trevor Weston said.
"We offer our sincerest condolences to the patient's family at this difficult time."
Health Minister Martin Foley said the time spent on hold was "under active investigation".
"Any death is a tragedy, but the death of a young child from a major incident like that is really, really traumatic for everyone involved," he told reporters on Wednesday.
It is not known whether the delay near-two-minute delay contributed to thedeath.
Foley said emergency departments, hospital wards and paramedics had been dealing with "record levels" of demand following the rise of Covid-19 cases.
Earlier on Wednesday, AV's Mick Stephenson said paramedics had noticed longer delays at hospitals "than we've ever had before".
"Our capacity to respond and our performance has never been challenged as much as it has been over recent weeks," he told ABC Radio Melbourne.
"If the growth in Covid cases continues, performance will be expected to get poorer unless we can do something about reducing the number of people coming into hospital."