More than a week since he announed his return to frontline politics, former prime minister Ehud Barak has still not chosen a name for his new party.

But he is already in full campaign mode, hiring advisors and enlisting new candidates.

On Tuesday he announced the arrival of Noa Rothman, the granddaughter of slain prime minister Yitzhak Rabin. Ms Rothman follows prominent Labor party member Ya-Ya Fink and Sagit Peretz-Deri, a lawyer and activist who was until recently a member of Jewish Home.

Mr Barak is also giving combative interviews and releasing campaign videos daily, most of them lambasting Prime Minister Benjamin Netanyahu — but also with some sly digs at his rivals in the opposition.

For the other centre-left parties, matters are less frenetic. On Tuesday, under half of Labour Party members turned out to vote for their new leader.

Three candidates were on the ballot and 47 per cent voted for Amir Peretz, who led the party between 2005 and 2007 and served as defence minister in Ehud Olmert’s Kadima government.

The other candidates, Stav Shaffir and Itzik Shmuli, representatives of a much younger generation of Labour activists, who came to prominence in the social justice protests of 2011, made do with just over a quarter of the vote each.

As Mr Peretz arrived on Wednesday at party headquarters to give his victory speech, the rather small crowd assembled did not greet him with the customary chants of “the next prime minister is coming!”.

Labour plummeted to just six seats in April’s election and no-one in the party that ruled Israel for half its history has any illusions that it will be forming a government in the foreseeable future.

But even if Mr Peretz succeeds in creating some momentum for Labour, the opposition’s main problem is of having too many parties playing on the centre-left field.

The new leader of Meretz elected last week, Nitzan Horowitz, has long been a vocal supporter of Meretz and Labour running together in a joint list. Mr Barak has also called for “new connections” and said repeatedly that this was his intention in launching the new party.

But a partnership between Labour and the Barak party will be difficult to achieve.

Mr Barak made his previous comeback in 2007 by beating Mr Peretz and removing him from the Defence Ministry. Four years later, when most of the party members opposed remaining in coalition with Benjamin Netanyahu’s Likud, Mr Barak broke away from the party with four other MKs.

There is disquiet too in the other main opposition party, Blue & White, where the factions that formed the party less than five months ago are at war with each other. Moshe Yaalon, number three in the alliance and leader of the Telem party, has criticised the prime ministerial job share agreed between leader Benny Gantz and number two Yair Lapid.

Mr Yaalon claims that it weakens Blue & White’s appeal.

Meanwhile, members of Mr Lapid’s Yesh Atid party are insisting they remain in charge of the joint party’s campaigning machine, despite claims that it is too narrowly focused on its own core vote rather than broadening Blue & White’s message further.