Toto Wolff has slammed suggestions he has already guaranteed Esteban Ocon the race seat at Mercedes for 2020.

Furious about Ocon's clash with Max Verstappen in Brazil a fortnight ago, Red Bull official Dr Helmut Marko said the Dutchman had been taken out by "a driver who already has a Mercedes deal for 2020".

"It's a waste of time to comment even for one second on what Dr Marko says," Mercedes team boss Wolff told the Finnish newspaper C More.

Finn Valtteri Bottas currently drives for Mercedes, so when asked if there is any truth whatsoever to Marko's claim, Wolff insisted: "No, it's not true."

Wolff announced in Abu Dhabi that Frenchman Ocon will be Mercedes' reserve driver in 2019.

That is because with Lance Stroll taking his seat at Force India, the last available cockpit for 2019, at Williams, has now been filled by Robert Kubica.

"We knew that Williams had financial problems and that they had to find a certain budget," Ocon told France's L'Equipe.

"But it's not the end of the world. I will still be always in the paddock, still working in formula one, with my goal to return in 2020," he added.