In a tactical coalition move, MK Moshe Gafni announced Friday that his party United Torah Judaism (UTJ) will form a haredi bloc with Shas. The move appears to be a direct response to Yesh Atid's success, a party which prioritizes equalizing the burden of IDF and national service.
"Yesh Atid did indeed receive 19 seats, but UTJ and Shas together have 18," he told Army Radio.
He said his party agrees with Shas on the fundamental issues: "On the matter of the status quo, on the issues of religion and drafting yeshiva students. It is impossible to impose different lifestyles on one another, and for this reason I believe that at the end of the day, common sense will prevail."
"We will not rule out other parties but our principles are clear," Israel Radio quoted Gafni as saying.
Shas' spiritual leader, Rabbi Ovadia Yosef, also commented on plans of a possible united front. "We intend to unite into one negotiating team," he told members of Shas.
Their remarks came a day after Prime Minister Binyamin Netanyahu launched informal talks with Yesh Atid chairman Yair Lapid, but it may take weeks until a government is formed to succeed the current right-wing coalition.
Netanyahu hopes to form a coalition of at least 80 MKs to ensure that none of the parties in the coalition could topple him by leaving, including the 19-MK Yesh Atid faction.
Netanyahu and Lapid are expected to compromise on which parties will be included in the coalition.
Lapid and Netanyahu agree on including Bayit Yehudi and Kadima, but differ on the rest of the coalition. Netanyahu wants Shas and United Torah Judaism while Lapid prefers The Tzipi Livni Party.
Netanyahu is expected to give in on Livni being included and UTJ excluded, while Lapid will most likely agree to the inclusion of Shas. Those compromises would lead to the formation of an 81-MK coalition of Likud Beytenu, Yesh Atid, Bayit Yehudi, Shas, Kadima, and The Tzipi Livni Party.
Lapid campaigned on a promise to change policy on the highly emotive draft issue in a country where most men are called up for compulsory military service at 18.
He has also pledged to improve the lot for Israel's tax-burdened middle class including by forcing more of the ultra-Orthodox to join the work force instead of living off stipends for religious study.
Gil Hoffman and Reuters contributed to this report.