Kato said the new cases included 43 passengers and one crew member.
The quarantine, maintained because some passengers and crew got infected with the coronavirus, expires on 19 February unless it is extended.
Kato said the elderly would leave the ship on 14 February.
Overall, there are about 3,600 people on board the Diamond Princess, among them 24 citizens of Russia. No one of the Russians has been reported infected.