"The cardinals have not come for minor, cosmetic changes," Vatican spokesman Federico Lombardi said.
"It will be a new configuration on important points," he said, referring to reform of the Roman Curia that would increase powers of local churches.
The reforms could also change the role of the Secretariat of State, the central administration of the Roman Catholic Church, which has evolved into something of a state within a state.
The role of lay people would also change and there could be "novelties", Lombardi said, without adding any further details.