Prime Minister Junichiro Koizumi sent a message to Cambodian Prime Minister Hun Sen on Friday, congratulating the country on the selection the previous day of Prince Norodom Sihamoni as its new king, Japanese officials said.
"We hope for the continuation of your country's peace and prosperity and intend to keep supporting your nation-building," Koizumi was quoted by the officials as saying in the message.
The Royal Council of the Throne unanimously chose the 51-year-old prince as Cambodia's next king a week after his father, King Norodom Sihanouk, abdicated.