The wife of Japan's prime minister-elect has defended her husband's nickname, saying it is good that he is different.

Yukio Hatoyama, who won power in a landslide election and is vowing revolutionary change, is known by opponents and supporters alike as "the alien" for his quirky hairstyle and eccentric manner.

In an interview, his wife Miyuki Hatoyama said her husband would make historic changes in Japan and she defended his unusual nickname.

Ms Hatoyama says her husband earned his nickname because he is different from old-style Japanese politicians and is not motivated by personal interest or greed.

Mr Hatoyama will be sworn in as Japan's 60th Prime Minister later this month.