"The requests for judicial assistance are too vague," Folco Galli, a spokesman for the Federal Office of Justice, was quoted as telling the told the NZZ am Sonntag newspaper.
Switzerland needs more detail on the allegations against the two ex-leaders to establish whether they constitute crimes punishable under its law.
The newspaper said Bern had informed the Egyptian and Tunisian authorities of its position in diplomatic correspondence on March 30.
It would reconsider once their requests had been reworked, a process in which Swiss experts are expected to assist.
Galli told the newspaper a representative of the Federal Office of Justice has already visited Tunisia and a similar meeting was planned with Egypt.
Switzerland ordered the freezing of the assets of Ben Ali and Mubarak shortly after they were toppled in popular uprisings in January and February respectively.
Mubarak's is thought to have "tens of millions" of Swiss francs in Switzerland, according to the Swiss foreign ministry, which in January estimated the assets of Ben Ali and his entourage as "a sum in the two-digit millions".