A group who helped to run a Waikato car meet, in which some of the attendees attacked a milk tanker, say they do not condone that behaviour.
The windscreen of a Fonterra tanker was smashed with a hammer and its milk was released onto the road when it tried to pass through the meet early on Saturday morning in Waikato.
It happened near the intersection of Stokes Road and Orini Road, just north of Hamilton.
Video footage shows a group of people swarming around the tanker, opening the cab door and appearing to pull at the driver inside.
Significant amounts of milk can also be seen gushing onto the road.
The group, who spoke to RNZ through the rfbdaily Facebook account, said they were not able to control the crowd.
"We obviously do not allow these actions happening at the car meets and we try our best to filter these people away from the scene. Nothing goes perfectly - they should be responsible [for] their own actions - but we try our best to keep things in order."
They explained people were angry because the tanker did not slow down when approaching the intersection where the meet was, and hit one of the cars.
"Usually, tanker drivers are nice and always slow down and make sure everyone is safe before carrying on. This tanker driver didn't really [seem to] care about anyone ... someone could've been run over."
A police spokesperson said: "It is unclear at this time exactly what happened at the scene and the extent of the damage to the truck is yet to be established."
An investigation is ongoing and police have appealed to the public for their help to identify those involved.
"Anyone with information, video or pictures of the incident is being urged to fill out an online 105 report and quote file number 220320/4139," the spokesperson said.
No direct comment was made on whether the group that helped run the meet was helping police with their inquiries.
But they did say they were "trying our best to figure out the name of who opened the milk tanker and we are removing them from the scene".