The Renault boss, who respectively beat McLaren and Ferrari for the world championships in 2005 and 2006, said he does not believe his counterpart Ron Dennis that no-one except Mike Coughlan at McLaren knew about the 780-page dossier of Ferrari secrets.
Briatore said the biggest disadvantage compared to Ferrari this year was its rivals' lack of knowledge of the Bridgestone tyres.
"Had I only known Ferrari's weight distribution, or how big their tank is, if I had a bit of those documents, then we surely wouldn't be in this situation today," the Italian told La Gazzetta dello Sport.
McLaren is currently subject to the suspicions of the FIA about the espionage saga, but Dennis insists that his suspended chief designer Coughlan acted entirely alone.
Briatore charged: "Dennis says he's immaculate, but it's hard to believe him. No, I don't believe in his good faith.
"In a team everyone knows everything."
He also criticised Dennis for not yet sacking Coughlan, while Ferrari has on the other hand dismissed alleged McLaren informer Nigel Stepney.
"It's an extremely serious thing that he hasn't yet been fired," Briatore said, referring to Coughlan.
"All the team managers should say that in F1 there's no more room for them." (GMM)