Mercedes will face the tribunal following a private test with Pirelli in May at the Circuit de Catalunya in Barcelona.
Several leading figures in the sport are expecting sanctions for Mercedes.
Sauber team boss Monisha Kaltenborn told Auto Motor und Sport that "a contract can't overrule a law."
Red Bull's Dr Helmut Marko told Blick "a fine and a points deduction would be appropriate."
Germany's Sport Bild claims earlier rumours that Mercedes has proof - an email - of Charlie Whiting's permission to use its 2013 car, was wrong.
That report said Whiting gave only conditional approval, "only if all the other teams are informed and agree". In the FIA's press conference on Friday, Mercedes team principal Ross Brawn was reluctant to comment on these rumours.
"The e-mail, I don't want to comment on any matters of that sort that relate to what's going to come through in the Tribunal," he said.
Pirelli's lawyers advised Paul Hembery against attending the FIA's press conference at the Circuit Gilles Villeneuve on Friday.