Renault is not yet committing to supplying customer engines to McLaren beyond 2020.
At present, there are rumours that McLaren could switch to Mercedes power for 2021, with Williams inheriting the Renault deal.
The two British-based F1 teams are denying it.
"We have never talked to Renault," Claire Williams is quoted by Auto Motor und Sport.
And a McLaren spokesperson said: "We are happy with Renault."
Renault’s response, however, is notably different. Boss Cyril Abiteboul is not even committing to Formula 1 for 2020.
It is believed Renault is angry about the concessions made by Liberty Media to top teams Mercedes, Ferrari and Red Bull regarding negotiations over the 2021 rules.
Abiteboul said: "Our contract with McLaren runs until 2020.
"They are a good partner, even when they manage to beat us at the moment. But for us, first of all, the question is about what Formula 1 will do after 2020.
"After that we’ll see," the Frenchman added.