An electronic shield will be put up around the conclave to prevent the use of mobile phones and other devices that might allow communication with the outside world.
However, Lombardi denied a report in the Italian media that the cardinals will be searched as they go in and out of the conclave.
Among the things the cardinals have to do is draw lots for which rooms they get at the Casa Santa Marta, the hotel within the walls of Vatican City where they stay during the conclave.
The hotel also contains a suite where the newly elected pope will live for a few weeks before moving to the papal apartments.
The apartments were placed under seal after Benedict XVI left last week and must be renovated before the new pope can take up residence, the Vatican said.