North Korea said on Tuesday it had no interest in a summit with Japan and would reject any talks, state media KCNA reported, potentially worsening already-hostile relations between the two countries.

Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, said Japan had asked for a summit without preconditions, which she welcomed only if Japan was ready to "make a new start" without "being obsessed by the past."

Bilateral relations have been strained over disputes including the abduction of Japanese citizens by North Korea in the early 2000s and Japan's occupation of the Korean peninsula in 1910-1945 and its use of forced labour and sexual slavery.

Japanese Prime Minister Fumio Kishida declined to directly respond to Kim's comments, telling reporters late on Tuesday that Japan would continue its efforts to resolve issues with North Korea based on existing policies.

Kim said Tokyo had "no courage at all" to change history, after Japan raised the issue of the abducted Japanese nationals and Pyongyang's nuclear and missile programmes.

"This is proved by the attitude of Japan clinging to the unattainable issues which can never be settled and have nothing to be settled," Kim said in a statement released by KCNA.

She singled out remarks by Japan's top government spokesperson, Yoshimasa Hayashi, that the North's claim that the abduction issue had been resolved was "totally unacceptable."

North Korea admitted in 2002 to kidnapping 13 Japanese citizens decades earlier. Five abductees later returned to Japan, saying the others had died. But Tokyo believes 17 Japanese were abducted, and continues to investigate the fate of those who did not return.

Accusing Kishida of using bilateral ties as "political calculations," Kim said her country would reject any talks with Tokyo. (Reporting by Hyonhee Shin; Additional reporting by Satoshi Sugiyama in Tokyo; Editing by Muralikumar Anantharaman, Miral Fahmy and Bernadette Baum)