"Volkswagen is already in other racing series, with engines that are similar to formula one technology," he reportedly told Sport Bild magazine.
But while admitting Red Bull has been unhappy with its current supplier Renault in the new V6 era, Marko played down the VW reports.
"That (report) was a complete hoax," the Austrian told Die Welt newspaper.
"Our goal is to work with Renault to make an initial assessment at the grand prix of Austria; to put our data on the table and then either develop a plan to continue in 2015 or find a better way to improve our current situation as quickly as possible.
"That is the reality," Marko explained.
Marko does not, therefore, hide his disappointment with the Renault situation in 2014.
"There are massive problems not only for us but also for other teams with the Renault engine," he said.
But he denied reports Red Bull is prepared even to sue the French car manufacturer for losses accrued while the F1 engine crisis was being solved.
"That's nonsense," said Marko. "We're not suing anyone, especially not Renault. We're only lamenting the shortcomings of the engine.
"We also complain that Renault tackled the deficits that were made dramatically apparent in the pre-season tests too late in our view," he added.
Marko acknowledged that Renault's situation has improved markedly since the winter crisis, but he remains far from satisfied.
"It's not enough," he said. "We need to be capable of winning, and that's exactly the goal that we are aiming for with Renault."