Mr Rabin is preparing the ground for bringing the hard- line ultra-nationalist party Tzomet into his dovish government, with the intention of appointing Rafael Eitan, the notoriously anti-Arab former chief of staff, as police minister. And the religious nationalist party Shas is manoeuvring to rejoin the coalition.
Strengthening the hawkish wing of the government would bode ill for Israeli compromise in the Middle East peace talks, both on human-rights gestures towards the Palestinians or on the settlers. The coalition negotiations are being watched warily by Yasser Arafat, chairman of the Palestine Liberation Organisation, who wants a number of Israeli concessions before the talks re-start.
Mr Eitan - known as Raful - is loathed by Palestinians, and has wide support among hard-core secular settlers. It was he who proposed smashing the intifada by making life 'unbearable' for the Arabs, and who told the Knesset in 1983 that, after Israel had expanded its settlements, 'all the Arabs will be able to do is scuttle around like drugged cockroaches in a bottle'.
Meretz, the left-wing coalition party which wants Mr Rabin to take tougher action against settlers and favours a Palestinian state, has threatened to walk out of the government if Tzomet joins.
Some Israeli commentators say that, with his slim majority, Mr Rabin has little choice but to widen his coalition during this period of instability in the wake of the Hebron massacre. When elected, he had 61 MPs inside his coalition - including Meretz with 12 and Shas with six - giving him a majority of one in the 120-seat house. Since Shas walked out over a corruption row, Mr Rabin has to rely on the votes of two Arab parties with five Knesset members.
Mr Rabin fears a right-wing backlash if security problems escalate as Palestinians seek revenge, and has repeatedly expressed his unease about relying on the support of Arab MPs. Furthermore, some argue, Mr Rabin knows he must take tough decisions against the settlers, and only with some hardliners inside his government will he be able to push these measures through. Since he was elected in 1992, Mr Rabin has advocated 'peace through strength', saying that only a tough government can instil enough confidence in Israelis to make compromises with the Arabs.
However, Meretz MPs are suspicious of Mr Rabin's motives for inviting Tzomet, with five Knesset members, into the coalition. 'I fear he may have changed his mind on the peace process. He may have decided that he will now only try to implement the Gaza and Jericho accords and then go no futher,' said Dedi Zucker, a Meretz MP.