Jenson Button believes the punishment, if any, that will be meted out to Mercedes is unlikely to be too severe.
Nico Rosberg's pole position and race victory at the Monaco Grand Prix has been overshadowed by his team's three-day in-season test with Pirelli earlier this month.
Ferrari and Red Bull lodged an appeal with the Monte Carlo stewards over the weekend after it emerged Mercedes used a 2013 car to do testing in Spain.
Merc team principal Ross Brawn feels his squad didn't do anything wrong, but Red Bull counterpart Christian Horner says they were "underhand" while the FIA has referred the matter to the International Tribunal.
If Mercedes are found guilty then they could be punished with anything from a fine to race ban to points deductions.
Button, who finished sixth in Monaco, feels Mercedes would have won without the test and he also believes any punishment is likely to be kept to a minimum.
"Mercedes have done a great job and even without that tyre test I think they would have won the race," the McLaren driver is quoted as saying by The Guardian. "I think the teams that protested are more surprised that it happened. I can't see the result changing. I don't know what they can do, if anything at all.
"Maybe a slapped wrist. I think the teams that protested just wanted clarification because we'd all love to do 1,000km to understand [the tyres] a bit more because we're all so limited on testing."
Meanwhile, Ferrari team principal Stefano Domenicali says his team just want clarification on the issue as they would be keen to do some in-season testing if they are given the green light.
"We just want to know if this is possible," the Italian said. "If this is possible we'd be the first to raise our hands to make sure that we can do the same, because as you know Ferrari has been very pushy to try and do in-season testing on the track, and this is the reason why we wanted to understand this situation, no more than that.
"And if the decision can be opposite on what we believe, it's the right interpretation of course on our side, then we will need to react immediately and ask for this to happen I would say as soon as technically we can do something.
"Since two years I think it's clear that Pirelli, in order to do some testing, was asking for all the teams to do some running. But for us it's very clear that we cannot do that with the actual car, and that's why basically even if they didn't formally ask us, we believe that it's not possible to do it. Because otherwise, as I said, we'd be the first to be there in pole position."