The car came back on to the road just as the truck came over the bridge at Erua.
"The car really did not have anywhere to go after that and the truck impacted the left-hand side of it," the crane operator said. "It went straight underneath the front of the truck."
The car was shunted backwards 30-40m before coming to a stop.
"It was absolutely destroyed."
The driver of the truck was not injured.
Victim Support in Gisborne has been helping the family and a serious crash investigation is under way.
SH4 was closed between SH49 and SH47 from 9.20am until 1.45pm yesterday while the scene was cleared.
Nazareth Te Huna was part of the Wainui Surf Life Saving Club's junior surf programme.
"He was a really nice kid to coach and will be sorely missed," said club coach Dion Williams.
"The whole team feels the loss."
Wainui club president Salvatore Zame said the club would like to extend condolences to the family.