Party spokeswoman Maria Dolores de Cospedal said Prime Minister Mariano Rajoy ordered the audit during a meeting of party executives.
Newspapers have been reporting that the former party treasurer, Luis Barcenas, also allegedly distributed under-the-table bonuses to party leaders. Cospedal said an internal investigation would be conducted and that if the allegations were determined to be true, anyone found to have received inappropriate payments would be expelled from the party.
Regarding Barcenas' Swiss bank account, the spokeswoman said the party "does not have and never has had bank accounts outside of Spain."
Although no arrests have been made or charges filed, the scandal comes at a difficult moment for Rajoy, whose country is suffering from recession and 25 percent unemployment.
Barcenas, who served for one year as the party's treasurer and 19 as its assistant treasurer, resigned in 2009 after he was first named in a National Court probe into alleged irregular financing practices by the party.
Cospedal also said Monday that the government would try to reach an agreement with opposition parties on combatting corruption.