The cordon was slightly relaxed within hours, but was still several hundred metres from the car.
One local farmer, who did not wish to be named, said he noticed the car earlier in the morning, around 8am.
He said the next time he saw it, about 9am, police cars were "swarming" to it.
The man said: "They were obviously pretty interested in it. They made us all go behind a cordon way down the road, but let us go back a while later.
"The police had parked their cars, and forensic guys pulled right up to the car, but have since parked further down the road. I guess, they are treating it suspiciously."
White suited forensic experts were seen examining the vehicle in the early afternoon.
Police urge anyone who has knowledge of the blue Honda Civic that has been located on Grays Road to contact the Op Gray inquiry team at the Papanui Police Station on 3637400 or Crimestoppers on 0800 555 111.