Opposition Leader Benjamin Netanyahu (Likud) met Monday with Rabbi Ovadia Yosef, the spiritual leader of the Shas party.
Netanyahu reportedly explained how important it was that Shas refrain from joining a government led by Kadima Chairwoman Tzipi Livni.
Shas had no official response to Netanyahu's claims.
While Kadima and Ehud Barak's Labor Party have reportedly agreed on the main clauses of their coalition deal, Shas is refusing to relinquish its demand for increased child welfare payments. Livni, for her part, is against any deviation from the State Budget.
Likud Knesset Member Gilad Erdan responded Monday to the reports suggesting that Kadima and Labor have struck a preliminary coalitional agreement, saying that "the public understands that midnight deals won’t make up for Livni's inexperience.
"Even if this clearance sale will give Livni and Barak a few more months in their seats – they will not escape the voters' verdict," he said, adding "If Shas joins this disgraceful government, which legitimizes giving up the Golan and Jerusalem, it would be the final act of betrayal against its constituency."
Amnon Meranda contributed to the report