As Motorsport.com revealed last week, Mercedes' rivals are pushing for a change of the rules for 2016 after the FIA closed off a loophole to allow engine improvement during the campaign.

However, with a rule amendment needing unanimous support, Mercedes could stand firm and say the rules need to stand, as it did last year.

It was only a direct challenge to the FIA over an interpretation of the regulations that opened the door for use of in-season development in 2015.

Mercedes concerned

McLaren racing director Eric Boullier has revealed, however, that there have been indications from Mercedes' senior management of a willingness to compromise.

When asked if he believed Mercedes would listen to the calls for change, he said: "Yes. I think they are already.

"And they are concerned. Speaking to Toto Wolff and Niki [Lauda], they are concerned about F1 itself. So I am sure there is some room for change."

Renault future in doubt

The issue of tokens has now become a key battleground between engine makers, as the performance gap between the four manufacturers appears to be quite large.

Renault's future has been thrown into doubt by Red Bull boss Christian Horner, who suggested that the French car manufacturer would not stick around if it could not keep developing its power unit.

Boullier said Honda was equally keen for the rules to be freed up.

"Our position is clear, we want to have as much room [for development] as possible," he said.

"Take our situation; obviously with the chassis you can develop it as you want. With the engine, you are locked into a situation when engine manufacturers cannot recover or cannot compete fairly.

"The regulations are the same for everybody and everybody knew the regulations before they entered F1, but there needs to be a degree of flexibility for that to change."