Sweden's voters left the country in political suspense after yesterday's still-undecided national election. But they also sent an unmistakable message to whoever finally wins control of the government: they want their taxes cut now.

Squabbling party leaders must wait at least until Wednesday to find out whether the three nonsocialist parties now in power or Olof Palme's challenging Social Democrats, who ruled Sweden for 44 years before being displaced in 1976, will win a single swing seat giving one bloc or the other control of parliament.

Under Sweden's system of proportional representation, the nonsocialist parties need 55 percent of 40,000 absentee votes to be counted by Wednesday to win that seat and a bare majority of 175 in the 349- seat, unicameral parliament. In the 1976 election, the nonsocialists won nearly 60 percent of the absentee ballot, the majority of which apprently is cast by more affluent conservative voters away from home on Sunday, Sweden's election day.

It appeared to be Sweden's more affluent voters who spoke loudest yesterday, making the right-wing Conservatives the largest nonsocialist party with 20 percent of the vote and at least 72 seats in parliament, 17 more than they won in 1976.

Most of their new voters were wooed from the centrist Liberal and Center parties by Conservative leader Gosta Bohman's vigorous campaign for cuts in Sweden's high income tax rate and limits on the growth of its expensive welfare state.

"The one thing we know about this election is that we did well," said Bohman, 68, a lawyer and former business executive. "We've got a policy people want. We take an interest in their practical problems, like taxes."

Bohman was needling his prospective nonsocialist coalition partners, Liberal leader Ola Ullsten, the current prime minister, and Center Party leader Thorbjorn Falldin. Their parties both lost ground after a confusing campaign in which they never offered clear-cut alternative polcies while appearing to shun both the Conservatives and the Social Democrats.

Sweden's traditionally stable voters became more poliarized than in the past. While the Conservatives gained the most on the right, the Social Democrats and Communists on the left both recovered more modestly from past losses.

Whether this trend will continue may depend on what a new government does about taxes. The obvious success of Bohman's tax-cutting oratory forced the Liberal and Center parties to propose their own plan to lower income tax rates and raise the cash allowances paid to Swedish parents with children at home. The Social Democrats also vaguely promised to do something about income tax rates here, which are Europe's highest.

First, however, a new government must be formed after an election in which the nonsocialist bloc and the combination of the Social Democrats and Communists finished in a dead heat, each with 49.2 percent of the more than 5.2 million votes counted by this morning. If the parties on the left had won, the Communists were expected to support a Social Democratic government.

Should the Social Democrats win, Palme, 58, a flamboyant, intellectual government leader in the early 1970s, would return as prime minister. He demanded today that Ullsten resign and allow Palme to take over immediately, since the Social Democrats remain the largest single party and hold the deciding seat in parliament pending the tally of absentee ballots and any recount.

But Ullsten, whose Liberal Party won only 10 percent of the vote, said he would not step aside until the final result was known. Staying on could give the urbane Ullsten, a 48-year-old former social worker, more bargaining power in negotiations over who would become prime minister if the nonsocialists win. It has been considered politically impossible for Bohman of the Conservatives to become prime minister even though his party is now the largest on the right.

Instead, Falldin, a square-jawed, 53-year-old sheep farmer who has led his former Agrarian Party on an ecological crusade, is the current favorite to become a coalition prime minister even though the Center Party fell from a 24 percent share of the vote in 1976 to just 18 percent.

Falldin gets along better with Bohman than Ulsten does, and the Center and Conservative parties appear to be fairly close on most policies except the question of nuclear energy. Falldin wants to curb Sweden's nuclear program, while the Conservatives believe that Sweden badly needs all the nuclear power it can generate to reduce industry's dependency on costly imported oil.

Falldin resigned as coalition prime minister over the nuclear issue last year, but he says he now would carry out whatever nuclear policy the Swedish voters decide in a referendum scheduled for March.

The only thing party leaders seem to agree on today was that a coalition between the Social Democrats and any of the nonsocialist parties was unlikely.

"We have seen how the parties in the middle have marched more and more to the right," Palme said. "So it is unlikely that there could be cooperation between us and any of the bourgeois parties. We have won the election. It is only a question of whether we have won the government."

"We have more in common than we disagree on," Bohman insisted. Yet at a press conference organized by Swedish television, Ullsten pointedly turned his back on Bohman as he answered a question about the coalition's plans and indicated that he and Falldin had discussed forming a coalition.