A back-seat passenger jailed for manslaughter after a 1998 crash in which the driver hit and killed a seven-year-old has sustained serious injuries in another crash.

Tee-Jay Crossan, now in his early 30s, is in Christchurch's Burwood Spinal Unit after a truck he was in plunged down a bank at a farm near Gore in October.

Crossan made legal history after he was jailed for three years after being convicted of manslaughter following the fatal crash in Gore. He was 18.

He was not the registered owner, but was found to be responsible for the car at the time of the crash, on January 17, 1998.

Police charged him because he allowed the car to be driven by 16-year-old Phillip Grigg, who crashed through a fence, hitting and killing Gore boy Samuel Kingsbury, 7.

Grigg, who was intoxicated and unlicensed, was also jailed for manslaughter.

Crossan lost an appeal against his sentence.

A parent who bought vodka for the teenagers was also charged.

In the latest crash, the truck - in which Crossan was again a back-seat passenger - plunged about 90 metres down a bank at a farm near Waikaia on October 12.

Emergency services were called to the paddock off Winding Creek Rd, north of Riversdale, just after 4pm.

Crossan was among a group of forestry workers who had finished for the day before the crash occurred.

Crossan suffered severe spinal injuries.

Yesterday, Crossan said he had "moved on" from the 1998 crash.

His focus was on his current recovery.

The prognosis was still uncertain but he was "hopeful for the best", he said.

Crossan said he was likely to continue therapy at the unit for at least a further five weeks.

Crossan said it "would all depend on the situation" whether car owners should be charged when drivers do something illegal while behind the wheel.

- © Fairfax NZ News