Aug. 1 (Bloomberg) -- Benjamin Netanyahu's Likud Party would form the biggest bloc in Israel's parliament if elections were held now, a poll found.

A majority of voters view Netanyahu, who served as prime minister between 1996 and 1999, as the ``most appropriate'' candidate to take over as premier from Ehud Olmert, a separate survey found.

The polls by the Yediot Ahronot and Ma'ariv newspapers were conducted yesterday, a day after Olmert, 62, announced he will step down as Israel's prime minister as soon as his Kadima Party chooses a new leader.

Likud would capture 33 seats in the 120-member Knesset, Israel's parliament, three more than in the previous poll on May 30, a survey by Teleseker for Ma'ariv showed. If Foreign Minister Tzipi Livni, 50, the frontrunner in the race to head Kadima, leads it into elections, her party would win 20 seats, down from 25 in May, according to the poll published today.

Olmert succumbed to pressure to resign in the face of six police investigations started since he took office 2 1/2 years ago. While Kadima may choose a leader as early as Sept. 17, Olmert could stay on as a caretaker until March if his successor fails to form a new coalition and the Knesset has to call elections.

Police Questioning

Israeli police questioned Olmert for a fourth time today over allegations that he took money illegally from U.S. businessman Morris Talansky and double-billed the government and non-profit organizations.

Investigators interviewed Olmert for about 3 1/2 hours at his official residence in Jerusalem over the allegations, police spokeswoman Orit Friedman said by telephone, declining to provide further details.

Kadima, formed in 2005 by then Prime Minister Ariel Sharon and colleagues who left the Likud because of its opposition to territorial compromise with the Palestinians, would gain fewer Knesset seats if the party were led by Shaul Mofaz, the transportation minister and former chief of staff, according to the poll for Ma'ariv.

Kadima would win 16 seats in the Knesset under Mofaz, down from 18 in May. While Livni backs peace talks with the Palestinians and Syria that Olmert revived this year, Mofaz has emphasized his opposition to compromise on issues such as dividing Jerusalem with the Palestinians or acceding to Syrian demands to return the entire Golan Heights in exchange for peace.

`Existential Threat'

Mofaz said in Washington today that Iran's nuclear program represents an ``existential threat'' to Israel, adding that the Jewish state must be ``prepared for every option.''

The Labor Party, led by Defense Minster Ehud Barak, would get between 17 and 20 seats, depending on who leads Kadima, the poll showed. Ma'ariv said it surveyed a representative sample of the adult population, without providing further details.

Under Israel's parliamentary system, voters elect the Knesset, whose members in turn choose the prime minister, traditionally the leader of the biggest faction. No Israeli party has ever won an outright majority of seats, so that the designated prime minister must enlist coalition partners to ensure a majority.

Netanyahu was deemed the most appropriate candidate for the post by 36 percent of Israelis, up from 29 percent in a previous poll two weeks ago, a survey for Yediot Ahronot by the Dahaf Institute found. The 58-year-old, while supporting peace, has said in the past he opposes a Palestinian state, which is the goal of the negotiations Olmert is conducting.

Livni Support

Livni was regarded as the best candidate by 30 percent and Barak by 15 percent, according to the survey of 400 people that had a margin of error of 4.8 percentage points.

Livni's support among Kadima voters is increasing, the Yediot survey showed. Among 500 people identifying themselves as party supporters, 41 percent said they would back her, up from 38 percent two weeks ago. Support for Mofaz declined by 1 percentage point to 32 percent, the poll found.

Israeli voters prefer early elections over any attempt by Olmert's successor to reconstitute his coalition, according to the Yediot poll. About two-thirds said they preferred elections, while 28 percent favored a new coalition.

To contact the reporter on this story: David Rosenberg in Jerusalem at drosenberg1@bloomberg.net.

Last Updated: August 1, 2008 11:55 EDT