"I do not share this optimism surrounding Ferrari," Briatore told Turrini's Quotidiano blog.
"I understand the feeling after the Barcelona test, but I doubt that the results are reliable," he added.
"I just cannot imagine Mercedes behind, with the margin of advantage they had until the end of November. I think the Germans have been hiding," Briatore said.
"I would settle for a more balanced championship, with competition between different names."
Briatore, who recently held a surprise farewell party for his friend Bernie Ecclestone, was also asked about new F1 owner Liberty Media's plans for the future.
"I do not enthuse about Liberty, who bought formula one but may not know what they have bought," he said.
"They want to make every grand prix like a Super Bowl, but what are they talking about? How do you do a Super Bowl in the middle of the Ardennes? Or in Malaysia, between the monsoon and the snakes?"