Almost 30 complaints have been made to the Ministry for Primary Industries about the mistreatment of animals in rodeo in the past five years - but no one has been prosecuted.
The ministry studied about 60 hours of footage out of about 300 last year, and found some minimum animal treatment standards weren't met.
Anti-Rodeo Action spokesperson Lynn Charlton has been filming rodeos for a couple of years and wanted the sport banned.
She provided footage to the ministry as part of a complaint, which showed the rope and tie event - where a calf is chased, roped and tied - going over the recommended 30 seconds.
"What we see at rodeos is nothing like a bull having a little kick-out, a little buck in the field. These animals are coerced into bucking," she said.
"They've had their tails twisted. They've had electric shocking, often to get them in or out their trucks. They know what's coming in the chutes because they've been there before."
The code was set by the National Animal Welfare Advisory Committee - an independent group that provides advice to the Minister for Primary Industries.
But the code has no legal basis and was only set to encourage high standards when caring for animals.
Any prosecution would have to be taken under the Animal Welfare Act, which sets a high bar to take a case to court.
Animal Welfare Compliance head Chris Rodwell said the ministry took complaints seriously.
"We've had over 300 hours of footage that has been supplied to us last year alone. Sixty of those hours we've looked at with animal welfare inspectors, a private independent vetinarian and there has been a number of [instances of] non-comformance with code," he said.
"The difficulty is that in order to bring a prosecution, you need to have what we call evidential sufficiency."
No one was prosecuted following the investigation, but the ministry had spoken to the New Zealand Rodeo Cowboys Association, Mr Rodwell said.
As a result, competitors were no longer required to tie a calf for six seconds for the rope and tie event, he said.
Further details on the investigation were requested from the ministry, but were not provided before deadline despite follow-up emails.
However, in a report provided to Ms Charlton, the ministry official said the footage submitted did not show excessively stressed animals in chutes, but some poor judgment could be seen.
One of the problems identified was having no one person responsible for making decisions on when to release an animal.
The ministry this year has also opened an investigation after footage at the Mid-Northern and Warkworth rodeos appeared to show young cattle being electric shocked.
The code states the electric prods should only be used on adult cattle.
Rodeo Cowboys Assocation spokesman Gary Jackson said rodeo club members throughout the country care about the animals, and any possible breaches were likely to be unintentional.
"It's probably caused by the moment. What they call breaches, you would have seen a couple [of] bulls jump up at the chute," he said.
"Now the code says any unruly animal should be removed from the chutes. But that's not an unruly animal. That's just an animal that gets a fright."
Animal welfare activists focused on rodeo because it has a public profile, Mr Jackson said.
"They don't understand what we do. They don't understand the animals. We don't apply any difference to the animal welfare in rodeo than what we do in our work as stockmen, farmers and farm managers," he said.
The ministry will soon have new powers to deal with animal abuse, including the ability to issue compliance notices.
Out of the 1500 minimum standards across all codes of welfare, 91 new enforceable rules have been proposed.
The ministry plans to introduce three relating to rodeo: banning the use of electric prodders on animals under 100kg, the use of goads - a type of prod - on sensitive areas of an animal, and fireworks at rodeo events.
Insight this week investigates rodeos and how animals are treated, after the news at 8am on Sunday.