Prime Minister Benjamin Netanyahu has been looking into running a joint Likud ticket with Avigdor Lieberman's Yisrael Beiteinu party in the general elections, Haaretz has learned.

Netanyahu apparently fears the three main center-left parties - Labor, Kadima and Yesh Atid - will field a joint list in the elections, scheduled for September 4, that would be the largest bloc, enabling them to form a government.

Open gallery view Yisrael Beiteinu chairman Avigdor Lieberman at a Foreign Ministry meeting in Jerusalem, April 3, 2012. Credit: Olivier Fitoussi

Such a list could win more than 40 Knesset seats in the elections, recent public opinion polls predict. Labor is expected to win 18 or 19 Knesset seats, while Kadima and Yesh Atid are expected to glean 10 or 11 seats each, according to the polls.

In the outgoing Knesset, Kadima had 28 seats and Labor initially had 13 - a total of 41 seats - before Ehud Barak split from Labor with four other MKs to form the Atzmaut faction, leaving Labor with eight seats.

According to the law, the president must grant the leader with the highest chance of forming a government the mandate to do so. The prime minister's associates fear that even if Likud, right-wing and ultra-Orthodox parties together get more Knesset seats that the center-left bloc, the president's mandate will go to the largest single faction.

All the polls released this week predict the Likud will win some 30 Knesset seats and Yisrael Beiteinu about 15. Theoretically, a joint Likud-Beiteinu list would be larger than the center-left bloc and receive the president's mandate.

But the chances of Kadima, Labor and Yesh Atid forming a joint list are slim, mainly due to personal rivalries and differences, political sources said.

It is hard to imagine any of these parties' leaders - Shaul Mofaz, Shelly Yacimovich or Yair Lapid, respectively - agreeing to have either of the other two named head of the joint list and candidate for prime minister.

Mofaz, a former defense minister and chief of staff, does not deem Yacimovich suitable for prime minister, his associates said.

Yacimovich, who according to the polls stands to win twice as many Knesset seats as Mofaz, has already declared herself the bloc's candidate for prime minister, as the leader of the larger faction.

Observers say a merger of these lists could drive left-wing voters, who object to Mofaz, into the arms of Meretz leader Zahava Gal-On.

In contrast center-right voters, who are currently supporting Kadima, will balk at the prospect of voting for Yacimovich and shift their support to Likud, observers said.

A senior Labor source told Haaretz on Wednesday the possibility of a joint list cannot be ruled out, although it has not been discussed yet.

Likud sources said yesterday that a merger between their party and Yisrael Beiteinu would only be possible as a response to a center-left bloc.

Lieberman's aides said he was not familiar with the issue.