As the Israeli election campaign enters a critical week — the last one in which candidates’ lists can be filed with the Central Election Commission — there is frenetic activity on all parts of the political spectrum, as smaller parties on the right and left rush to cobble together joint lists.

On the right, there are currently four parties jostling with each other. On Sunday evening, the New Right, which very narrowly failed in the April election to pass the electoral threshold, announced that it would run again with former Justice Minister Ayelet Shaked in the top position.

The place was relinquished by the party’s co-founder, former Education Minister Naftali Bennett. Ms Shaked polls as one of the more popular right-wing politicians and this is creating headaches for the United Right List electoral alliance.

The two main parties which comprised the alliance — Jewish Home and National Union — have already agreed to run together again, but their dilemma is whether to run with Kahanist Jewish Power, its third wheel in the last election. The alternative is to accept the New Right leaders, who themselves left Jewish Home only seven months ago.

Party leaders Education Minister Rafi Peretz and Transport Minister Bezalel Smotrich have expressed willingness to create a wider right-wing party, but are less comfortable with Ms Shaked taking the top spot.

They are also under pressure from Prime Minister Benjamin Netanyahu not to field a joint list with New Right and instead to join Jewish Power again.

Mr Netanyahu has a number of considerations. He is concerned that the leaders of New Right are no longer committed to supporting a government led by him and would prefer to prevent a situation where Ms Shaked, who fell out with him and his wife twelve years ago, leads a larger party.

His other concern is that should the three right-wing parties link up, some of New Right’s more moderate voters might go elsewhere, perhaps to Yisrael Beiteinu, led by Avigdor Lieberman, who is in private vowing to end Mr Netanyahu’s rule.

Another small right-wing party, the libertarian Zehut under Moshe Feiglin, which also failed to pass the threshold in April, is also trying to join one of the other lists and will almost certainly not run on its own.

The turmoil on the centre-left is, if anything, even more intense. Last Thursday night, Labour leader Amir Peretz announced that Gesher, the centrist party led by Orly Levi-Abecsis that was another victim of the electoral threshold in April, would be running together with Labour.

Mr Peretz proclaimed that he would be targeting right-wing voters and ruled out further mergers with other parties. This caused unrest in Labour, and prominent members are among those joining Meretz and former prime minister Ehud Barak’s Democratic Israel party's in a left-wing alliance.

The defectors include the former Labour leadership candidate Stav Shaffir, who on Thursday announced she was joining the “Democratic Camp” ticket, led by Meretz's Nitzan Horowitz. Ms Shaffir will take the second slot while Mr Barak will be in tenth position, a major gesture.

Mr Barak had earlier made an additional gestures to Meretz, issuing a public apology for the deaths of 12 Israeli-Arab protestors back when he was prime minister in 2000.

But it appeared unlikely that Mr Peretz would be adding Labour's lot to the ticket.

Further to the left, the four parties of the Arab “Joint List” are still trying to work out their own alliance, after failing to do so in April and running as two separate factions.

The current argument is over the places after position number 10, and the Arab nationalist Balad is still unclear if it plans to run for the Knesset, or to become an non-parliamentary movement.

They all have until Thursday night, when the lists have to be handed in to the Central Election Commission.