The four men worked locally as farmhands but Ms Stewart said their names would not be released until their families had been notified.
She said initial investigations indicated the car lost control on a slight crest on the unsealed road, slid across the road, flipped and crashed through a fence and landed on its wheels in a paddock.
Three of the men were thrown from the vehicle and police said it was not known if anyone inside had been wearing a seatbelt.
Local woman Dianne Torr was on her way to work at 7.30am when she noticed headlights in her neighbour's paddock.
"I went and had a look and that's when I saw the body. Two occupants had come out of the vehicle and they were face down. I could tell they were dead. The two younger guys were inside the vehicle,'' she told APNZ.
"It had glanced off a willow tree, went through a fence and rolled.''
The two older men were believed to be friends who lived together on the farm where they worked, not far from the crash site, said Mrs Torr.
She rushed to the nearby home of a fire officer to raise the alarm.
Meanwhile, a 19-year-old man was killed when he was hit by a car on Birches Rd in Lincoln just after 2am.
Police would not release his identity but said the teenager was a local.
Another man died and three people were injured when a car hit a power pole south of Stratford in Taranaki last night.
Firefighters had to cut two people from the wreckage on Mountain Rd shortly before 9.30pm.
An elderly woman who had stopped her car with possible engine trouble was killed when she was hit by a car on State Highway 2 in Otane at Hawkes Bay last night.
Inspector Paul Jermy said it would have been dark when the woman stepped out of her car just before 6pm.
- HERALD ONLINE, APNZ
