The party said that due of road blocks and other special security arrangements related to the performance, there was a fear that voters would not be able to reach polls and thus, the decision was made to delay the vote.
The primaries were meant to be held on July 3rd.
About a month ago, former minister Avi Gabai and MK Amir Bar-Lev announced that they would both be running for Labor leadership.
MK Amir Peretz has also joined the fray, saying he intends to run for party leadership and MK Erel Margalit, who has yet to officially announce his joining the race, is expected to make his announcement as well.
It is unclear whether MK Eitan Cabel—who is embroiled in controversy surrounding a "secret deal" with MK Shelly Yachimovich involving mutual support—intends to run or not.
The party secretariat said that if in the first round of primaries no candidate receives more than 40 percent of the vote, a second round will be held between the top two candidates on July 13.
The deadline for announcing candidacy for party leadership is set for May 1.
(Translated and edited by Fred Goldberg)