The Trinity model is 1.5 to 2 years behind schedule, Schaefer said, speaking to Wolfsburger Allgemeine Zeitung and Wolfsburger Nachrichten.
The model was delayed in part because it was taking longer than expected to develop hands-free autonomous driving technology and get regulatory approval.
By the time it is ready, production of some combustion engine cars may have already ended in the main Wolfsburg plant, creating space to build the Trinity there instead of investing in a new factory, he explained.
"Will Trinity come? Yes. Whether a new plant will be built is another question," Schaefer said.
Reuters reported in mid-November that plans for the Trinity plant, budgeted at around 2 billion euros ($2.10 billion) with construction to start in 2023, were in doubt as new Chief Executive Oliver Blume reshuffled the carmaker's production strategy.
Schaefer's comments were the first public explanation of why the factory may not be built.
"The chances are 50:50," he said. "By late January, early February we will know which cars will be made in which plants on what platforms."
While order books were still full into mid-next year, the brand chief also warned incoming orders were slowing down as consumer sentiment darkened.
The carmaker was also facing "flat-out chaos" on the supply side, he said, with the Wolfsburg plant making well under 400,000 cars a year - less than half its capacity because of missing parts.
Suppliers were cancelling deliveries of 100,000 parts with one night's notice, Schaefer said, and chips were selling with up to an 800% price surcharge.
"It's a catastrophe for the business," he said.
($1 = 0.9514 euros)
(Reporting by Victoria Waldersee, Jan SchwartzEditing by Miranda Murray and David Evans)
By Victoria Waldersee
