Two police officers have been injured after being "pelted with rocks and bottles" after a 200-car burnout gathering in Levin.
Police vehicles were also damaged in the incident overnight to Sunday, Manawatu Area Commander Inspector Ross Grantham added.
"Around 30 police staff, deployed to the area pre-emptively, were put at serious risk due to the aggressive behaviour of many of those involved," he said.
The aggressive behaviour followed a large gathering on Bath St about 8pm. More than 200 cars, each with multiple passengers, were in attendance.
"The convoy of vehicles then converged at the intersection of Queen Street and State Highway 57, before attempting to do burnouts at this location," Insp Grantham said.
"Police staff managed to disrupt the activity and move them on, but not before patrol cars were kicked by bystanders, who also threw bottles at the cars.
"The group then moved to Miro Street in Otaki, where they proceeded to do more burnouts."
Insp Grantham said due to a risk to staff, police chose to avoid actively engaging with the alleged offenders in the industrial cul de sac.
However, the group then headed back to Levin, to the intersection of State Highway 57 and Tavistock Rd, where they blocked the road and did more burnouts.
"A police patrol attempted to drive through the group to disrupt them, however the observing crowd turned on the officers, kicking and bottling the car. The side window of the patrol vehicle was smashed," Insp Grantham said.
"Police were able to disperse some of the traffic, and drivers then headed to the intersection of Queen Street and State Highway 1."
Officers on foot, armed with protective shields, attempted to disperse the crowd, but when officers turned into Oxford St the crowd had grown significantly and turned violent, Insp Grantham said.
"People threw bottles, rocks, and bricks at the retreating police. Two officers received minor injuries from items hitting their legs."
Two men have so far been arrested.
"Six cars were impounded, one person was arrested for disorderly behaviour, and another was arrested for obstruction," Insp Grantham said.
The man arrested for disorderly behaviour was allegedly wearing a stab-proof vest and carrying a large knife, while the man arrested for obstruction was allegedly found to have a flick-knife in his possession.
Insp Grantham said the allegedly armed offenders was a concern.
"This is incredibly concerning, as it indicates that the crowd was not just car enthusiasts, but included people out to deliberately provoke, aggravate, and endanger," he said.
"To ensure the safety of officers, further anti-social driving behaviours such as burnouts were observed from a distance, and officers will be utilising footage taken and received, to follow up on illegal behaviour.
"Police absolutely understand the stress and concern illegal and anti-social street racing causes members of the community, and we are committed to disrupting this activity by breaking it up when it occurs, and holding offenders to account.
"However, this is an example of how incredibly dangerous these situations can become, and I'm very proud of my staff who put themselves in harm's way. Police go to work every day to help make our communities safer, and behaviour such as this which prevents officers from doing so is entirely unacceptable."
He said police would be utilising tools such as CCTV, and other information gathered at the time, to follow up any other criminal offending.
"Police thank everyone who reported concerns to us, and appeal to anyone who has information on illegal or unsafe activity to report this to police via 105 with as much detail as possible."
