Junichiro Koizumi's Liberal Democratic party on Sunday night scored a landslide general election victory, vindicating the prime minister's decision to dissolve parliament early and turn the poll into a referendum on postal reform.

The win, the biggest landslide since Yasuhiro Nakasone's in 1986, virtually assures the LDP four more years in control of the powerful lower house, although Mr Koizumi repeated his pledge to stand down as party head and prime minister next September.