The boys, who were all left shaken by what happened, were asked by police in the wake of the assault what had been said.
Mr Clinton said the boys said they were just "clowning around" and that the boy had yelled out "hi" to the man - and that he appeared to take it the wrong way.
"But regardless of what might have been said these were just kids being kids - this boy got a real hiding."
Mr Clinton said the young victim, who was later treated at Hawke's Bay Hospital for superficial injuries and discharged, told police the man approached him and grabbed him by the throat.
"He then allegedly punched the victim and put him in a headlock, and this caused him to fall down a stock bank."
Mr Clinton said the man then allegedly went down the bank after the boy then chased the boy down the bank, reapplied the headlock and kicked him in the back before making off.
The three boys ran to the nearby car park and raised the alarm.
The man rode off but about 30 minutes later returned to the area and was seen by a member of the public who gave chase but was unable to get to him as he cycled off in the direction of a nearby sports park.
"This was a savage and prolonged attack by a grown man on a boy barely able to defend himself," Mr Clinton said.
"It was a seemingly unprovoked and diabolical attack carried out and in public in broad daylight - it could have been so much worse for the poor young fella."
He said the boy was left "pretty shaken up".
The youngster had been holidaying from the Bay of Plenty and been staying with his grandparents in Taradale.
Mr Clinton said the man had been riding a white mountain bike with a large black rear mudguard and police wanted to hear from anyone who may have seen him riding in the cycleway area, or know his identity.
Police can be contacted on 06 837 0100 or by anonymously contacting Crime Stoppers on 0800 555 111.