The Rodeo Cowboys Association says it will launch a review after a bull climbed through a fence and rampaged through the crowd at the Outram Rodeo on Waitangi Day.
A witness says spectators ran for their lives after the agitated animal managed to somehow slip through the fence.
She believed people could have been killed as the bull ran amok.
Speaking on condition of anonymity, the witness said she and her children loved rodeo and did not want to see it banned, but called for fencing improvements to prevent similar incidents in the future.
NZ Rodeo Cowboys Association president Lyal Cocks said the fence met the requirements of the Rodeo Code of Welfare and was the stipulated height of 1.8m.
Cocks was not at the rodeo on Wednesday and said he had yet to see a bull escape from an arena.
However, the association would launch an investigation to see if there was any way to prevent a recurrence of the incident, he said.
"We'll be doing a review to determine if there is anything we can do to prevent it."
The witness said the incident happened about 10am, during the second division bull ride.
The bull bucked its rider before walking down the fence, eyeing spectators, the witness said.
"It was eyeing up the crowd ... it went person to person down the fence."
To the horror of spectators, the bull scaled the fence and managed to squeeze through.
"It jumped and it broke the netting, then it went over the wire and just rampaged."
"We took off up the bank with everyone else, just running.
"It went towards the bar, then it turned and came our way ... it was rampaging, it was charging."
Something then distracted the bull, she said.
It turned the other way and ran away from the arena, before jumping over fences and through paddocks, eventually reaching a dairy cow paddock 2km away.
The woman was still shaken yesterday, but the incident did not appear to have dulled her or her family's enthusiasm for the sport.
"We've seen a lot of rodeo over the years and I love it. My kids love it. These stock handlers are amazing with the animals. And, let's face it, a lot of these animals wouldn't be around if it wasn't for rodeo."
Outram Rodeo Club president James Adam said he was unsure how the bull managed to scale the fence and slip through, describing it as a "freak accident".
Club members would be inspecting the fence to insure its integrity, though there were as yet no plans to raise its height ahead of next year's rodeo, he said.
The bull had not previously shown any signs of jumping but was now retired from rodeos.
"He's back home now with the rest of the bulls ... we wouldn't take him to another rodeo."