Ferrari says it will be impossible to close the gap to Mercedes during 2014 thanks to Formula 1's engine freeze rules.
The FIA demanded that manufacturers homologated their power units before the start of the season, with improvements only allowed to be made on reliability grounds.
And with all three car makers getting close to optimising the performance of their packages, there is now little scope for a dramatic change in the competitive order over the remainder of the campaign.
When asked how much could be done to close the gap to Mercedes thanks to the freeze, Ferrari team principal Marco Mattiacci said: "You know a lot about F1, I don't know why you say 'close the gap to Mercedes'.
"The regulations do not allow you to work radically to close the gap, so it will not be true to say that we can close the gap. What you can work on is reliability."
Mattiacci's doubts were echoed by Fernando Alonso, who agrees there is no scope for catching Mercedes.
"There's too much difference," he said. "We cannot touch the engine, we cannot make big changes."
The double F1 champion is more optimistic about 2015.
"In one year many things can happen and we saw some cases in the past where one year from another many things can change," Alonso explained.
"Especially this year we are very new, so I expect in 2015 there will be big steps from everybody, including Mercedes. So we will all be better next year.
"Definitely the team that starts with a lower baseline has a bigger margin to improve, so we will get closer or at the level of Mercedes, that's our hope.
"We need time. It's not a job that you can do in one day but our intention is to get there."