Animal activists planning a protest outside the Martinborough Rodeo are calling it a form of legalised cruelty and claim animals are regularly abused.
Wellington Animal Rights Network spokesperson Hannah Lessells said rodeos sent the message to young children that it was okay to torment and abuse animals for fun.
It was embarrassing that New Zealand was falling so far behind overseas trends, with parts of the United States now moving to ban rodeos, she said.
But Martinborough Rodeo organiser Shane Bird has rejected the claims that animals are abused at the event.
He said despite the planned protest, rodeo was a legal sport in New Zealand and they followed the law.
The animal welfare code existed to stop any cruelty towards animals and they stuck to the rules of the code, he said.
Mr Bird said the perception that they were breaking the laws or bending the rules was not true, and people should come along and see for themselves how the animals were treated.
The SPCA has collected 42,000 signatures on its petition calling for a ban on rodeos, which will be submitted to Parliament next month.