While the exact number of vehicles damaged while at Awamoa Park, bordering State Highway 1, had yet to be established, at least two instances were reported to police over the weekend.
One vehicle had its rear tail light smashed and a rear panel damaged, and a stereo was stolen from another after a lock was forced open.
Sergeant Blair Wilkinson, of Oamaru, said police were aware of other vehicles that had also been damaged.
There have been multiple reports of vehicles being damaged, tampered with, having fuel siphoned from them or being stolen from the park in recent years, which prompted pleas from police for people not to leave vehicles parked there overnight.
Sgt Wilkinson said police could not stop people from parking their vehicles at the park, but advised them that if they did so they risked being targeted.
"We would just advise people that if they are using that location to sell their cars, taking them away and parking them at home overnight is going to be the safest course of action.
"Obviously, a lot of people are putting their cars up there for sale and if you do that, there is a risk with them being up there overnight.''
No arrests had been made and inquiries were continuing, he said.
For years people have parked vehicles (including cars, boats and caravans, among others) they wished to sell privately at the end of a sealed driveway by the Awamoa scout group den.
While break-ins and at times thefts are not uncommon, few incidents are reported to police.
The last reported incidents were in mid-August last year, when a vehicle and a yacht were broken into.
Later that month all four rims and tyres were stolen from a late-model Subaru.
Eighteen vehicles were parked at the park yesterday morning.
