Stefano Domenicali says Ferrari only supports the addition of a 14th team to the field because it believes the erstwhile BMW Sauber squad deserves to be on the grid, and would not otherwise be in favour of a 28 car entry.
BMW Sauber lost its guaranteed slot in the 2010 Formula 1 entry when the parent company announced it would pull out of the sport next season.
That meant the FIA invited a fresh round of applications for the 13th place in the entry, which was eventually won by the revived Lotus team.
Just hours after that announcement, it was revealed that BMW Sauber had been saved by the Qadbak organisation, and would go onto a reserve list pending the FIA's efforts to get the other teams to agree to expanding the field to 28 cars to accommodate Sauber.
Williams has publicly opposed this on the grounds that F1 cannot handle the logistics of a 14-team pit lane, and believes most others in the paddock support its stance.
But Domenicali says Ferrari definitely wants Sauber to be allowed back in because the team has been a loyal supporter of F1 and is already a proven quantity.
"It's very clear on our side," said Domenicali.
"We would be very happy [to have 14 teams] because we feel it would be a shame to lose a new like Sauber which is finishing on the podium.
"We respect their tradition, and they have structure.
"We feel that we can agree to that kind of exception for them."
Domenicali underlined that in normal circumstances Ferrari wanted no more than 13 teams in the field, and that if anyone else dropped out they should not be replaced.
"If someone is not ready then I think it's correct to stay with 13 teams, also because we've always said we would like to think towards three cars per team in the future," he said.
"Only if it's Sauber, and then if someone leaves then we go back to 13 - no replacements."
Ferrari has agreed to supply Qadbak/Sauber with engines if it can secure a 2010 entry.
The Sauber team had a long and successful history in sportscars - including running Michael Schumacher as a Mercedes junior - before coming to F1 in 1993.
Its achievements were limited to podium finishes before BMW took it over as the basis of a factory team in 2006, although founder Peter Sauber retained a shareholding and the squad till worked largely out of Sauber's Hinwil base.