Japan Post has begun delivering refrigerated parcels overseas through an exclusive deal with Japan Airlines, but the future of the tie-up remains murky due to JAL's limited cargo services and intensifying competition with rival delivery firms.

Japan Post Co., the postal service arm of government-owned Japan Post Holdings Co., started shipping refrigerated parcels to Taiwan and Singapore in April and to Hong Kong in October on a trial basis. The service started from shipping centers in Tokyo, Hokkaido and Kanagawa Prefecture, and will start next month from Osaka Prefecture and Kyushu.

But Masatsugu Hisada, senior manager of Japan Post's international business division, is concerned about the delivery times.