The ruling tripartite coalition on Sunday split over the timing of the Liberal Democratic Party's presidential election, with the LDP's partners signaling that they want a successor for lame-duck Prime Minister Yoshiro Mori as soon as possible.

LDP policy chief Shizuka Kamei said Mori should implement the coalition's emergency economic package before the poll is held.

"Prime Minister Mori should decide on his own when to call the presidential election. If the prime minister thinks it is better to let someone other than him do it (implement the package), he will be irresponsible," Kamei said on a Fuji TV program.

The remarks by Kamei, who chairs the LDP's Policy Research Council, contrast with the main view within the LDP that the presidential poll should be called before the package is set in motion.

"The emergency economic package will be high on the agenda at the Japan-U.S. summit. He (Mori) cannot say 'I will not do it and advance it (the LDP presidential poll)' after pledging to carry it out at the summit," Kamei said.

The LDP presidential election was originally set for September, but Mori, facing increasing pressure to resign, moved it up. Many LDP members are worried that the LDP will lose the House of Councilors election in July due to Mori's extremely low popularity.

Mori left Sunday evening for Washington to hold his first summit with U.S. President George W. Bush on Monday to discuss issues such as economic problems involving the two nations.

But key policymakers in the LDP's coalition partners -- the New Conservative Party and New Komeito -- called for an early LDP presidential poll and urged the LDP to deal with its timing separately from implementation of the economic package.

New Komeito leader Takenori Kanzaki said early implementation of the emergency economic package is necessary but that it is a separate issue from the LDP presidential election.

"LDP Secretary General Makoto Koga has said it will be held as soon as possible, so I hope so," Kanzaki said in a speech at an NCP-sponsored party in Nagoya.

"It is important for the three ruling parties to reorganize a stable regime as soon as possible to win the House of Councilors election" in July, Kanzaki said.

NCP Secretary General Takeshi Noda joined Kanzaki in calling for an early LDP presidential election to pick a successor to Mori, who has agreed to bring forward the presidential race from September.

Faced with record-low ratings, Mori has been under pressure from many LDP members to resign amid concern the LDP will be clobbered in the Upper House election if he stays on.

"It (the timing of the LDP presidential poll) should not be linked necessarily to the issue of (when to implement) the emergency economic package," Noda said on an NHK talk show.

Noda hinted at his reluctance to see the LDP find a successor to Mori after legislative steps are taken to enact the economic package in June.

"The Cabinet of Prime Minister Mori should draft the economic package by the end of this month . . . There will be legislative work on implementing the package and they will be subject to Diet deliberation. All necessary procedures will not be completed until June," Noda said.

Meanwhile, New Komeito Secretary General Tetsuzo Fuyushiba expressed hope that former LDP Secretary General Hiromu Nonaka, an LDP power broker who played a key role in forming the coalition with the the New Conservative Party and New Komeito, will replace Mori as LDP president.

"He is a man of promise. He is the person most sensitive in taking care of people around him among people I have ever seen," Fuyushiba told a TV Asahi program.