Three car makers have been named as potential candidates to enter Formula One after the engine rules change in 2013.
Jean-Francois Caubet, managing director of F1 engine supplier Renault Sport F1, said "Volkswagen, Honda and Hyundai" could launch forays when the turbocharged four-cylinder power plants replace the current 2.4 litre V8s.
His comments are a further sign that engine makers back the FIA's greener rules for 2013, amid Bernie Ecclestone's fears that spectators and sponsors will not appreciate the loss of the current engine note.
I don't think they will come in the first year, because that would be difficult for a car manufacturer
As for the aforementioned three, Caubet said they are likely to watch the implementation of the new formula in 2013 and then make a decision.
"I don't think they will come in the first year, because that would be difficult for a car manufacturer," he told motorsport-total.com. "Maybe later."
Renault Sport F1 supplies engines to the Renault, Red Bull and Team Lotus teams.