The leadership battle will pit a conservative, who has alienated Japan's Asian neighbours, against a liberal seeking to make amends with them.
The opposition has demanded snap lower house elections, arguing the Liberal Democratic Party no longer holds the people's mandate and has no right to choose the prime minister.
The leadership upheaval in the ruling party follows a humiliating defeat at polls for parliament's upper house in July. Before Abe quit, his popularity ratings had sunk to about 30% because of the scandals and resignations involving some of his key ministers.
The LDP announced on Saturday that dovish Yasuo Fukuda and conservative Taro Aso will square off on September 23 for the party's presidency - a post that assures selection as Japan's prime minister - after Abe's sudden resignation on Wednesday.
The premier was later hospitalised for exhaustion and stress-related stomach problems, leaving behind political confusion in the world's second-biggest economy.
"The totally unexpected has occurred," Fukuda told a press conference on Saturday.
"I've decided that I have the responsibility to step up in this time of crisis."
Meanwhile, Aso, 66, a high-profile member of Abe's Cabinet, has moved to distance himself from Abe, who lasted only a year in office and suffered a series of setbacks over financial scandals and gaffes involving his ministers.
Aso has sharply conservative views, and once suggested that Taiwan benefited from being colonised by Japan in the first half of the 20th century. He also drew protests from Beijing for saying China was a military threat. He is expected to push a hawkish foreign policy stance, in line with Abe.
Last Mod: 15 Eylül 2007, 12:15