Two more people have been arrested over an incident in Hamilton where hundreds of litres of milk were emptied from a tanker and the windscreen smashed.

Videos circulating online show milk pouring out of the tanker on Orini Rd, as well as people surrounding the vehicle as it appears the driver tries to keep his door closed.

A significant amount of milk was emptied from the tanker and a hammer was used to smash the windscreen during the incident, which happened on March 19, police said.

The driver of the tanker was not injured.

An 18-year-old male was arrested and charged with wilful damage, disorderly behaviour likely to cause violence, and possession of an offensive weapon last month.

Now police have arrested two more people in relation to the incident, Waikato West Area Commander Inspector Will Loughrin said.

They arrested a 17-year-old male on Thursday after executing two search warrants, he said.

"Police located two imitation firearms at these search warrants."

A member of the public had spotted one of the imitation firearms during the incident.

The 17-year-old will face charges of unlawful possession of an imitation firearm, inciting disorderly behaviour and sustained loss of traction.

Police have also charged a 19-year-old man with sustained loss of traction.

He also had his vehicle impounded and is due to reappear next month in the Huntly District Court.

"Police take this type of offending very seriously and these arrests are a clear indication of that," Loughrin said.

"We welcome help and information from the community which can help us prevent this type of antisocial behaviour.

"This type of behaviour won't be tolerated and we will continue to actively investigate and act on information provided to us."

Officers are still on the hunt for two more 18-year-old males.

"We are committed to holding all offenders to account and keeping our roads safe."

Anyone with information that could help police with the investigation can call 105 and quote file number 220320/4139.

One person told the Herald the tanker hit two cars and tried to drive off.

"The event had two groups of people attending. One group attacked the tanker while the other crew defended the tanker. The attacking group is not part of the normal car scene in Hamilton."

A young woman was reportedly injured as she tried to protect the tanker driver.

Another girl was reportedly shoved into nearby scrub and was stood on, the person said.

"The milk discharge was done by someone in the video who is clearly visible, this person has since been dealt to by his father.

"The tanker driver is a little shaken but unharmed thanks to the efforts of the local Hamilton car crew and their actions defending the driver and doing their best to stop the attack."