"It gives me a special feeling to try to go to the Olympics to represent Japan", the two-time Grand Slam champion told the broadcaster in an interview in Tokyo.
Osaka now holds dual nationality from Japan and the United States. "I think that playing with the pride of the country will make me feel more emotional".
Osaka, who has a Japanese mother and a Haitian father, told NHK she has completed an administrative step to obtain Japanese citizenship ahead of her birthday next week.
The two-time Grand Slam victor has opted to keep her Japanese nationality, as under USA and Japanese legislation, a person with more than one citizenship must choose one before they turn 22 years old.
She had a disappointing end to the US Open, getting eliminated in the Round of 16, but redeemed herself in the final of the China Open in the beginning of October, beating world No.1 Ashleigh Barty. The Japan Tennis Assn. lists her as a national team member.
Osaka, who will turn 22 next week, plays under the Japanese flag in Women's Tennis Association events and the Fed Cup.
She clinched her maiden grand slam title when she beat Serena Williams int he US Open final previous year and backed it up with victory in he Australian Open in January to become one of Japan's biggest and most bankable sports stars.