It has triggered rumours Red Bull is on the lookout for a new engine supplier.
Reports have emerged that Cosworth, without a customer for the 2014 season, has nonetheless completed its turbo V6 design that will not be raced this year.
The wilder rumours indicate Red Bull could take over the project and run its own engines for 2015.
When asked about the split rumours, Renault Sport's Remi Taffin told Sport Bild: "I know nothing about that.
"We are currently working very closely with Red Bull, and several teams of (Red Bull) engineers are even at our base in Viry and working on the integration of the power unit and chassis."
Red Bull's Dr Helmut Marko also told the German publication: "We have a long term contract with Renault, which is of course linked with our results on the track.
"Nevertheless, we are not going to panic and are making a joint effort to solve the problems."
World champion Vettel also sounded calm about the current situation, whilst admitting he hopes to finally get up to speed this week in Bahrain.
"Of course the Jerez test did not go the way we wanted," he said. "Other teams did a lot more kilometres and that was important because we are talking about completely new technology.
"But it's better to have the problems in testing than at the races.
"Hopefully the situation in Bahrain will already be better, and I'll have a car not only that goes around the track, but that I can use at full throttle."