TOKYO - TARO Aso, the front-runner to become Japan's next prime minister, said on Saturday Tokyo should be alerted of any threat from 'murky' North Korea, ahead of voting to replace the moderate incumbent.

'The top leader of the murky state is unstable,' Mr Aso said, referring to North Korea's Kim Jong Il who is reportedly ill after suffering a stroke.

'It is just so dodgy,' Jiji Press quoted Mr Aso as saying in a speech delivered in southwestern Saga city.

'Japan has to prepare surely for addressing' emergency situations, including the possible collapse of the isolated communist state, he said.

The outspoken former foreign minister, known for his hawkish views, is the favourite to replace unpopular Prime Minister Yasuo Fukuda in an election Monday for the leader of the ruling Liberal Democratic Party, who will also become premier.

Tensions in the bilateral relationship are centred on North Korean kidnappings of Japanese civilians in the 1970s and 1980s.

Mr Fukuda, regarded as a moderate on North Korea, agreed in June to relax some Japanese sanctions after Pyongyang said it would start a new probe into the fate of the abductees.

Some analysts have said an Aso government may be a throwback to Mr Fukuda's predecessor Shinzo Abe, an outspoken conservative whose career was marked by tough talk on North Korea. -- AFP