The government began preparing Sunday to send a disaster relief team to Sri Lanka following massive tsunami damage from a powerful earthquake that struck off Indonesia's Sumatra Island, Foreign Ministry officials said.
An emergency office was set up at the Foreign Ministry, the officials said.
Japan also asked the Indonesian government about the need for assistance.
The medical unit can leave Japan within 48 hours after a request, the officials said.
Ministry officials were checking on the safety of Japanese citizens living in or visiting the affected areas and received a number of telephone inquiries from the families of such people.
There have been no reports of Japanese being killed or going missing, according to the officials.
Japanese tour companies were also busy collecting information on the safety of their customers traveling in the region.
"We have heard that the airport in Pattaya (Thailand) has been closed," Yoshihiko Iwase of Kinki Nippon Tourist Co. in Tokyo said. "We might have customers who change their schedule for yearend trips."
The Osaka branch of Thai Airways International said it received calls from customers asking about the schedule of flights for the Thai resort of Phuket and the conditions there. Some have already canceled flight reservations.
The airline expected more people to cancel their bookings.