If there's anything that Israel does not need, it is more of the same kind of bizarre coalition government that has ruled it for the past four years.

Yet that's exactly what Israel seems likely to get unless there's an unexpected shift in voter sentiment before next Tuesday's national election.As matters now stand, opinion polls show Prime Minister Yitzhak Shamir's rightist Likud party and Foreign Minister Shimon Peres' Labor party in the kind of deadlock that forced them together after Israel's previous general election in 1984.

Under the power-sharing arrangement produced by seven weeks of haggling following the 1984 voting, Peres and Shamir have taken turns at holding the posts of prime minister and foreign minister.

Though both leaders publicly oppose a continuation of this arrangement, both camps privately say the two parties may have to join forces again.

In some respects, the unusual coalition has worked better that Israel had a right to expect. The coalition government has succeeded in reducing triple-digit inflation, withdrawing Israel's 1982 invasion forces from Lebanon, and reviving relations with Egypt, the only Arab country to make peace with Israel. Moreover, Labor and Likud see eye-to-eye to some extent. Both oppose talks with the PLO, favor an "iron fist" policy to crush Arab unrest, and ultimately support direct Arab-Israeli talks to reach a peace settlement.

But the government has failed to quell the Palestinian revolt. While Labor favors withdrawing from much of the West Bank and Gaza, Likud opposes any territorial concessions. Moreover, the job switching executed by Peres and Shamir has at times put Israel in the position of switching back and forth between tough stances and conciliatory positions, leaving their neighbors understandably confused. Continuing confusion can't help resolve the Middle East's old and bitter enmities.

Israel seems bound to remain stuck with some kind of coalition government as long as its electoral system remains unchanged. The present system lets a political party win a seat in the 120-member Knesset, or parliament, by capturing only about 20,000 votes, less than 1 percent of the total. That encourages the proliferation of small parties, 25 of which are represented in the current election. And the more parties there are, the harder it is for one of them to gain outright control.

Whatever the outcome of the Nov. 1 balloting, Israel urgently needs to overhaul an electoral system that amounts to a continuing invitation to unwieldy coalitions.