Prime Minister Ariel Sharon has finally decided on a name for his new party, after rejecting National Responsibility and Hatikva (Hope) as possible titles.
Pundits say Sharon has caused a political earthquake in Israel
The breakaway centrist party has been registered under the name Kadima, the Hebrew word for "forward".
The group, whose announcement on Monday redrew at a stroke the entire political landscape, is due to convene in Tel Aviv for the first time on Thursday.
At least 14 MPs from his former party, Likud, have joined the new faction.
Cabinet minister Haim Ramon - formerly of Labour - became the first senior member of the centre-left party to join forces with Mr Sharon.
Israel has set 28 March for early elections - which became necessary after Mr Sharon lost support of hardline Likud members over the Gaza pullout and faced a split in his coalition with Labour.
Several opinion polls in Israeli newspapers on Tuesday suggested that Mr Sharon's breakaway party could win the election, but the BBC Jerusalem correspondent says much may change in the coming weeks.
Israeli media reports say Likud's central committee - which is also meeting today - is preparing to set 19 December to start their leadership primaries.
Correspondents say the Likud candidates have turned on one another in the media after Mr Sharon's departure from the party.
Foreign Minister Silvan Shalom has accused Defence Minister Shaul Mofaz and former PM and leadership favourite Binyamin Netanyahu of "tearing Likud to shreds" with their campaigns.
"They've begun smearing and battling that is damaging to the party. The Likud today is in a state of distress and it is terribly irresponsible of them to get into internal wars," he said in an interview with Yediot Aharonot newspaper.
Mr Mofaz said of Mr Netanyahu: "As finance minister he hurt a lot of people in Israel. Now it is going to take a few years to repair the damage.
"The Likud members are intelligent people.... they realise that Bibi will reduce the number of Knesset seats they have."
In response, Mr Netanyahu - who has saved his harshest language for Mr Sharon - said the "wave of populist attacks... is bad for Israel".
Following the Israeli Prime Minister's split with Likud, Mr Netanyahu accused Mr Sharon of being a "dictator" and his family of "widespread corruption".