Video of a woman screaming at customers in the Hawera McDonald's has surfaced online.
In the clip posted to Reddit the young woman can be seen cursing at two men who were transporting cows in their trucks.
"There are cows on that f***ing ship and they're alive and they have souls!" the woman can be heard screaming.
It's likely the woman is referring to a livestock ship exporting 4000 cows to China for farming, which departed Port Taranaki on Friday.
Its departure was met with protests by animal rights activists who say the live export trade causes significant stress to animals.
A McDonald's spokesperson told Newshub the incident occurred on Friday night, when the woman began "acting aggressively" in the store.
"From the staff report the person was directing abuse at two truck drivers who were ordering food," they said.
"Seems like they were transporting cows, and the person has come in and started yelling at them."
The woman can be heard screaming expletives at the two truck drivers.
"And you don't give a f**k all of you in this room, but I hope when you die, you get to meet all those souls," she yells.
"Cow souls?" one of the men can be heard asking, sparking a brutal screech from the woman.
"Yes you f***er!" she yells back before advancing on the men.
"Don't, don't cause I will call the cops," a staff member can be heard saying.
The staff member then tells the woman to get out of the store. As she leaves the men can be heard taunting her.
New Zealand Vegetarian society says it sympathises with the woman in the video.
"We, too, feel profoundly sad when we consider the way animals are used and abused for profit and pleasure," said spokesperson Phillip McKibbin.
"We understand that, when people learn how bad the food industry's treatment of animals really is, it can prompt strong emotional responses."
However the organisation does not condone the woman's behaviour, saying vegans and vegetarians should be respectful in all their encounters.
"Persuasion and example setting are much more effective forms of advocacy."