A former acting secretary general of the opposition Democratic Party of Japan said Sunday he will call for replacing party head Yukio Hatoyama in January if the re-elected leader fails to live up to expectations.

"Even the Liberal Democratic Party replaced Prime Minister Yoshiro Mori because, with him on top, it couldn't have won elections," Seiji Maehara told reporters, referring to the resignation of the unpopular Mori in April 2001. Current Prime Minister Junichiro Koizumi succeeded Mori as LDP leader and prime minister.

"If our party can't gain control of the government or doesn't see public support ratings improve, we'll have to pick a new leader," he said.