Most rodeos have complied with the law in recent years, the Ministry for Primary Industries (MPI) says, despite some breaches of the code outlining rules around the controversial activity.
Anyone responsible for the welfare of animals used in rodeos is bound by an MPI code of welfare which outlines the standards they have to achieve to meet their obligations under the Animal Welfare Act 1999.
This outlines minimum standards of care across eight areas - ranging from stockmanship, food and water, equipment, to "emergency humane destruction".
When this code was revised in 2014, it included several new requirements to better protect animal welfare, an MPI spokesman said.
"This includes minimum standards that prevent the use of pyrotechnic displays and sheep riding events at rodeos, and strengthened standards for some equipment.