Fifteen to 20 Japanese nationals remain missing in parts of southern Thailand, including the resortisland of Phuket, Kyodo News reported Wednesday.

"It may take more than a month to identify all the bodies," Kyodo quoted a Japanese dental expert who is in the process of identifying bodies in Phuket.

Masatsugu Hashimoto, assistant professor at Tokyo Dental College, has been dispatched by Japan's Foreign Ministry to Thailand to help collect fingerprints and teeth marks of unidentified bodies.

He was quoted as saying that he has received data on the physical characteristics of about 20 missing Japanese from their families via the ministry.

The foreign ministry said Tuesday it has received 3,327 inquiries on the whereabouts of Japanese nationals since the Dec. 26 earthquake off Indonesia's Sumatra Island and subsequent tsunamis in the Indian Ocean.

It said it has been unable to contact 69 people.

The Japanese death toll from the disaster rose to 24 in Thailand and Sri Lanka on Tuesday.