BUENOS AIRES, SEPT. 7 -- The stunning resurgence of Peronism and the blow dealt President Raul Alfonsin's centrist party in yesterday's national elections have shoved this renascent democracy into a new period of political uncertainty.

But politicians and commentators said today that the democratic process had been strengthened by the vote, which gave greater stakes in the system to the opposition -- both the reformed center-left Peronist movement and the small center-right Democratic Center Union.

The scope of the Peronist victory had not been foreseen by opinion surveys. The prolabor movement captured more than two-thirds of the country's 22 governorships and substantially increased its representation in Congress at the expense of Alfonsin's Radical Civic Union. The Radicals lost their absolute majority in the lower house. With this sudden redrawing of Argentina's political map, Alfonsin was under pressure to revise his nearly four-year-old government, especially its economic policy.

The Argentine leader spent the day with senior ministers and political advisers. A presidential spokesman dismissed speculation about immediate changes in the Cabinet and said Alfonsin would take some time to analyze and reflect on the election outcome. But local news agencies reported later that all Cabinet ministers had submitted their resignations for the president's consideration.

There was broad agreement among members of Alfonsin's party and opposition leaders that the election results showed discontent with the government's economic management -- a "punishment vote," Peronist victor Antonio Cafiero called it.

Monthly inflation figures have jumped into the double-digit range in recent weeks, for the first time since mid-1985. Real incomes are eroding, and the national trade imbalance has widened.

Peronist leaders, closely aligned with the country's powerful labor unions, have been demanding a halt to interest payments on Argentina's $54 billion foreign debt, saying the funds should be spent on social programs, public works and industrial development. Alfonsin has said a moratorium would hurt the economy.

Despite this and other policy differences between the country's two main political groups, there were indications that the Radicals might seek some form of coalition arrangement with the newly reinvigorated Peronists. Antonio Troccoli, minister of interior and a veteran Radical politician, said last night that the Peronists would "share in the administration."

But as the parties turned their attention to presidential elections in 1989, it was unclear whether the Peronists really wanted a power-sharing arrangement or whether the Radicals would accede to the opposition's conditions.

"I think it's unlikely we'll join the government," said Guido di Tella, a senior Peronist economist elected yesterday to Congress. "We'll put forward conditions that would make it impractical."

Instead, di Tella predicted, Alfonsin may try to form a political alliance with center-right parties, although the tightening of economic measures which that probably would entail is also fraught with political risks.

The Peronist victory was all the more astonishing given the unpopularity and disarray into which the working class-based movement had slumped in recent years. From its rise in the mid-1940s, the organization, formally called the Justicialist Party, had been the dominant political force through several decades -- and a main target of repeated military interventions in politics.

Restored to power in 1973 elections, it floundered after the death of founder Juan Peron in 1974. Two years later, the military forcibly removed Peron's wife, Isabel, in a coup triggered by months of political violence and economic chaos.

The party's loss to Alfonsin in the 1983 presidential race, which revived democracy, set off an internal power struggle between an authoritarian Old Guard and a more democratic wing labeled the Renewal Peronists. The head of this moderate Peronist current, Cafiero, 64, an economist, former minister and onetime ambassador to the European Community, led the party to victory yesterday by winning the governorship of giant Buenos Aires Province.

Nearly final official figures showed the Peronists taking 16 or 17 of the country's 22 governorships, including those in such former Radical strongholds as Buenos Aires, Mendoza, Entre Rios and Misiones. The Radicals were left with only two governorships for certain -- Cordoba and Rio Negro -- and possibly Tucuman. The others went to provincial parties.

In congressional totals, the Peronists' scored 41.4 percent to the Radicals' 37.3 percent.

This cost the Radical party its absolute majority in the lower house, but because only half of the chamber's 254 seats were at issue, the Radicals still constitute the most numerous bloc. They won an estimated 52 seats, meaning they will have a total of 117 in the new Congress. The Peronists claimed 60 seats, bringing their new total to 108. No seats were contested in the Senate, where neither party has an absolute majority.

Also making a significant gain was the center-right Democratic Center Union, which raised its representation in the lower house to seven from three seats. Leftist parties lost seats.

Cafiero's crucial triumph made him a primary contender for the presidency two years from now, even though the Peronist leader pledged throughout the campaign to complete the four-year gubernatorial term if elected. Historically, the governorship has not been a springboard to the presidency. But Cafiero's electoral success is expected to unite many of Peronism's disparate groups behind him.

Alfonsin is constitutionally barred from seeking reelection. But his party's defeat left the Radicals with even fewer proven vote getters to run in Alfonsin's place in 1989. This gives new urgency to the Radicals' plan to reform the Constitution and allow either for reelection of the president or the establishment of a parliamentary system, with a prime minister's post tailor-made for Alfonsin.

The chances of such a change are now generally seen as having dimmed in the shadow of the Peronists' rise.