TOKYO, July 11 (Reuters) - Japan's prime minister would likely call a snap election for parliament's powerful lower house if the ruling camp loses big in a July 29 upper house poll, a leader of the ruling camp's junior partner said on Wednesday.

Prime Minister Shinzo Abe is struggling to soothe voter anger over mismanaged pension records and political corruption, and to allay doubts about his leadership after three ministers exited his cabinet -- two by resignation and one by suicide.

"If there is an upset, there will be political confusion and laws that need to be passed will not be able to be enacted," Toshiko Hamayotsu, acting representative of the Buddhist-backed New Komeito party, told Reuters in an interview.

Hamayotsu, an upper house lawmaker and a pivotal figure in mobilising votes for her party, said Abe's Liberal Democratic Party (LDP) would first try to woo independents and like-minded members of the main opposition Democratic Party if the coalition fell short of a majority.

"If lawmakers from the Democratic Party or independents join the Liberal Democratic Party and a majority can be maintained, there would not be a lower house election soon," she said.

"But if a majority cannot be maintained even by such means, a lower house election would occur. It's hard to say, but it could be within the year. It depends on the scale (of the loss).

Hamayotsu said that while a general election would not change the situation in the upper chamber directly, a ruling camp victory in the more powerful lower house would spark a reshuffling of party allegiances, helping to break the deadlock.

FORECAST OR THREAT?

Some analysts expressed doubts over whether the ruling camp would risk an early election for the lower house, where it now holds a huge majority.

No general election need be held until 2009.

"This is a warning for the people: 'If we lose, we'll have confusion or a lower house election'," said Toru Umemoto, a forex strategist who analyses politics at Barclays Capital. "It's a message to the people to vote for the coalition party.

The LDP and the New Komeito need to win a total of 64 seats to keep their majority in the upper house, where half of the 242 seats are up for grabs. The New Komeito is aiming for 13 seats.

A loss would not eject the ruling camp from government, since the lower house picks the prime minister.

But a big defeat for the ruling camp would make it difficult to enact laws and would put pressure on Abe to resign.

Hamayotsu, 62, admitted the ruling camp faced a tough election battle, but declined to predict the outcome.

"It is true that overall, it's very tough for the LDP. The wind is blowing in favour of the Democratic Party," she said, adding that this trend was natural since the opposition did not have to match its slogans with effective policies.

Hamayotsu said the New Komeito itself had a good shot at achieving its goal of winning 13 seats, but added that her party was feeling the heat of voter anger over the bungled pensions and concern about political corruption.

"We are facing the same sort of criticism we always face in elections, plus we are also feeling the adverse winds that are blowing towards the LDP and the coalition," she said.