Police, ambulance and volunteer fire crews attended the incident on a residential building site at Highview Tce after the Placemakers-branded Hiab toppled about 2.30pm.
Acting Sergeant Grant Miller, of Queenstown, said the man, who was transported to Lakes District Hospital in a moderate condition, was "very lucky''.
"He was unloading [the Hiab] using the crane at the back and it toppled over.
"It's a big, massive crane fixed to the back of the truck and you operate it by remote control.
"He would have just been standing on the ground, away from the truck working the remote control.
"Where he was trapped was right in the middle on the downhill-side of that load, so he was very lucky.''
A dog in the cab of the truck was freed by members of the fire brigade and was not injured, Sgt Miller said.
The truck was metres away from a neighbouring property and a boat when it fell.
It was not clear whether the driver was employed by Placemakers or the Hiab had been hired by a third party.
A Placemakers Queenstown spokeswoman said the company was unable to comment at this stage.
No further information was available yesterday afternoon.
