Mercedes team principal Toto Wolff has suggested his F1 rivals have been breaking the rules this season with regard to the legality of the floors of their cars.
From the Belgian Grand Prix onwards, a new technical directive comes into force that clamps down on the use of a so-called flexi-floor via the use of the skid block.
It is understood a number of teams have been able to run their cars closer to a track surface via the use of a moveable floor, in particular, areas within the skid block that ensure a car's plank suffers less wear than is permissible.
In using such a floor, a car's front ride height can be adjusted to ensure a greater level of performance.
The FIA has apparently been alerted to what has been at play following its decision to improve the overall safety of F1's cars in the wake of the porpoising effect.
Assessing the significance of the clampdown, which will see stiffer floors required on all cars from the Belgian GP onwards, Wolff remarked: "And some [teams] have said that it [a flexi-floor] doesn't exist.
"As a matter of fact, some teams have skids that actually disappear when the car hits the bottom.
"The reason for skids is that they are the limitation of how much plank wear you can have, and if a skid can disappear miraculously into the floor, that is clearly against the regulations."
Wolff airs F1 cars plank deflection concerns
Teams have been given an additional month's grace to change the floor designs of their cars as the FIA had originally intended to introduce the TD from this weekend's race in France.
Another area of concern for the FIA is the movement of the plank itself, which Wolff is confident will be clarified ahead of next season.
"The second thing is a plank that deflects or moves away more than the tolerance should be," added Wolff.
"The tolerance is one millimetre and if the plank moves away many more millimetres into the car, obviously, you gain more performance there, too.
"The first one [re skid blocks] is going to disappear for Spa because apparently skid material is not available, and the second is going to be clarified in next year's regulations.
"That is still in discussion to put it all out in the open."
Red Bull boss Horner - "Total rubbish"
Wolff did not name any teams he felt were breaking the rules.
Red Bull team principal Christian Horner described as "total rubbish" any suggestion his organisation was complicit in circumventing the regulations.
"We’re getting issues mixed up here," said Horner. “Maybe he [Wolff] is referring to cars that are around him at the moment. I have no idea, but I have absolutely no issues or concerns on our floor.”
Ferrari, on the other hand, is one team that will be making changes.
Team boss Mattia Binotto said: "There will be some changes which will be required because now a new clarification has been issued with new tests which are required on the new specification.
“It will take some time, so at least it's good to relax it [the TD] to Belgium because [with porpoising] not being a subject, there is no need to rush.”