Injured 5-year-old Hugh Christie waited beside his dead dad up to five hours for rescue after a horror car crash on Monday in the Hunter Valley in New South Wales.

In what seems an agonising miracle, Hugh sustained only a broken arm and nose in the four-wheel-drive crash that killed his father Paul Christie, 42, his grandfather Bill Christie, 75, and Hunter Valley real estate agent Adam O'Regan.

Then he waited up to five hours for help amid the wreckage.

Hugh was the sole survivor when the vehicle plunged 400m down a steep embankment, throwing the occupants from the vehicle on Monday, the Daily Telegraph reports.


"You can only imagine the trauma that [Hugh] has been through," Hunter Valley Police Acting Superintendent Guy Guiana said.

Hugh's shattered family has released a statement saying they are grieving the loss of "a husband, brother and son, and a husband and grandfather".

"Our son, who thankfully sustained non-life threatening injuries, is understandably shaken and it is our family's number one priority to be there and care for him as he recovers," the family said.

"We request peace and privacy at this incredibly difficult time for our family."

Police believe Hugh waited five hours for help to come after the four-wheel-drive the group was in plunged down a steep embankment off a track as O'Regan was showing the Christie family a remote property at Gundy, near Scone, on Monday.

O'Regan was thrown from the vehicle and died at the scene, along with the two Christie men, whose bodies are believed to have been found side-by-side.

Police believe Bill Christie survived the initial impact, and may have crawled to his son before succumbing to his injuries. They believe tiny Hugh may have tried to use a mobile phone to call for help during his five-hour wait for rescue.

Police believe O'Regan was trying to turn around on a track on the property when his four-wheel-drive lost traction.

Wendy Christie, Hugh's grandmother, has extended her condolences to O'Regan, a much-loved member of the Scone community, and thanked everyone involved in the recovery operation of the men.

Bill Christie was a retired radiologist-turned-cattle farmer. Hugh's father, Paul, lived in Balmain with wife Linda, Hugh, and daughter Hattie.

He was the proud coach of his son's rugby team.

- additional reporting AAP