Two Formula 1 teams have admitted their opposition amid rumours that Mercedes are preparing to help Honda finally get up to speed in F1.
The rumour has been taking shape in recent weeks, and in Barcelona it emerged that the Austrian company Avl might also get involved to help Honda finally end its reliability and performance crisis.
Mercedes chief Toto Wolff, however, is not confirming the rumours.
"Honda is a large and prestigious company," he told Spain's El Mundo Deportivo.
"They're in a difficult situation now but I'm sure they will find a way out and do not need our help."
Yet amid the rumblings, there are already signs that some of Mercedes and Honda's rivals are not happy with the plan.
Renault-powered Red Bull's Dr Helmut Marko said: "I don't know if it's true, but I don't think it's a good idea.
"There are already very strict rules about cooperation with regards to the chassis."
Amid a sea of 'no comments' elsewhere, Bob Fernley admitted that as Force India's deputy boss, he would not be happy if Mercedes started working with Honda.
"As a team that's not only paid for [Mercedes] engines but contributed to the development of them, I would certainly be very negative towards sharing that technology with another team that is a competitor of ours," he said.
Mercedes currently lead the constructors' rankings by eight points to second-placed Ferrari.