Police were yesterday still investigating the cause of the accident, which occurred about 8.45am, but said the tanker and the silver Mazda sedan were both travelling south towards Kingston when they collided.
Both vehicles ended up on the right-hand side of the road, with the car facing the truck.
The car was badly damaged in the front and on the driver's side.
Fire crews removed the doors to enable to the driver to be freed and treated by ambulance staff. Constable Phil Bayne, of Queenstown, said the extent of the driver's injuries was unclear, but he was conscious and stable when taken to Lakes District Hospital.
The man was later flown by helicopter to Dunedin Hospital for further examination. No details of his condition were available last night.
The female passenger, also an American tourist, escaped without serious injury, but according to police was "very shocked'.
She was also taken to Frankton Hospital.
The male driver of the tanker escaped unharmed butdid not wish to talk to the media.
Fire Officer Dion Helmshaw said the driver of the tanker had sealed off the empty tanks and turned off all electronics as a safety measure.
Const Bayne said police did not have a clear picture of the cause of the accident and inquiries were continuing.
"We have not been able to speak to the driver of the car yet, so we have only heard one side of what happened from the truck driver.
"Without the full story, we cannot say exactly what happened," Const Bayne said.
