The split in the 14-member Shinui faction was authorized Thursday by the Knesset House Committee.
For the short remainder of the 16th Knesset, 11 of the former Shinui MKs will operate under a faction called the Liberal-Secular party.
Only three MKs, Ehud Rassabi, Ilan Leibovitch and Igal Yasinov have retained the Shinui title.
MK Avraham Poraz, who is heading the Liberal Secular group warned the Haredi parties not to rush to celebrate his political demise or that of the secular movement.
"I understand that the Haredi parties are happy that Shinui is splitting today," said Poraz. He noted that he has done this once before, when he along with the Shinui party split from Meretz in 1999. He said he got into the Knesset then and intends to do it again.
"Don't eulogize me," he warned. But his spokesman said that it is unclear whether he and the other MKs intend to form a new party or join an existing one.
MK Eti Livni, now of the Liberal-Secular Party, said she believes the group would form a new party, noting that it had until February 8 to register as such.
She believes that voters would chose them over Shinui because they have a proven track records. Those who are remaining in Shinui do not represent its ideals. The other centrist party is a supermarket of ideas.
"We're a boutique," she said.
The two groups are still meeting to discuss the terms of the split, including the division of NIS 11 million in funds, of which some NIS 2 to 3 million is expected to go to the new faction and group. The Liberal Secular politicians are also expected to retain office space in the same building in which Shinui has its headquarters in Tel Aviv.