Two more leading Red Bull-Honda chiefs have rubbished Toto Wolff's claim that Mercedes will not spend another "minute" developing the 2021 car.
Red Bull team boss Christian Horner has already insisted he "can't imagine" that Mercedes won't bring a single new part to the title battle this year.
Dr Helmut Marko also doesn't believe his fellow Austrian Wolff.
"Honorary Doctor Wolff talks as much as the day is long," Red Bull's top F1 official told f1-insider.com.
"We already know that Mercedes will not stand still. Of course they will try to make the car faster and we are prepared for that.
"In any case, we are continuing with our own program, which always included improving the car right from the start," Marko added.
Wolff insists that Mercedes must focus exclusively on next year so as not to fall behind at the very start of the new regulatory period from 2022.
"We were and still are sure that we will manage the balancing act between development this year and developing the car for the 2022 regulations," Marko said.
"We will certainly not rest on the lead we have now. We need to constantly give full throttle."
Engine partner Honda's F1 chief Masashi Yamamoto was also asked about Wolff's claim that Mercedes will no longer develop the 2021 car.
"I have the same opinion as Christian," he told the Japanese source as-web.jp.
"I don't think Mercedes or any top team would do that. We will continue to develop one race at a time for Red Bull and for the world championship."
