While the Irish vote today in what polls indicate should be a very close election, economists and business leaders warn that whoever wins must expect to raise taxes, curb government spending and preserve what has been a dramatic increase in the average Irish family's standard of living.

Both the ruling Fianna Fail Party and the opposition Fine Gael have promised more benefits from the economic and social revolution that has transformed Ireland in a generation from a poor pastoral society into a fast-growing industrialized society. But underlying the brief campaign have been problems that represent that price of this success.

Rising expectations of the work force and the price of energy to run new industries have fueled inflation. Investment in transportation and communications, continuing subsidies for new factories, and a burgeoning government bureaucracy providing social welfare have plunged Ireland deeply in debt.

Ireland's increasing trade has made it more vulnerable to global economic cycles. The electronics, pharmaceuticals, medical hardware and other high-technology industries attracted from overseas, particularly the United States, have prospered despite the world recession, but Ireland's traditional textile-making has been hit hard.

Farmers, suddenly enriched by higher European agricultural prices and special benfits after Ireland joined the European Common Market in 1973, have recently found their expenses increasing more rapidly than their income.

Unemployment has increased significantly despite the creation of tens of thousands of new jobs each year because young people are staying in Ireland to work instead of emigrating and others are coming back home from abroad. The birth rate is still high and half of the population is now under the age of 25. This promises an even greater employment problem in the near future.

In contrast to the smartly dressed, confident-looking young people who fill the new offices, factories and housing subdivisions of Dublin and its suburbs, where a third of Ireland's 3.5 million people now live, idle youths left behind crowd inner-city slums and public housing. They are blamed for the rapidly increasing robberies and attacks on police, as well as the rioting last month after the deaths of Irish nationalist hunger strikers in British-ruled Northern Ireland.

Other social charges also are evident. Many more women are entering the labor market and running for public office. Pressure is increasing for liberalization of restrictive laws on divorce, abortion and the sale of contraceptives, as well as for generally reducing the influence of the Roman Catholic Church in the running of the country.

There are no ideological differences between the two major parties on these issues. Fianna Fail and Fine Gael, with roots in the nationalist movement that led to the creation of an independent Ireland 60 years ago, support the continued expansion of Ireland's private economy with extensive assistance from the government. And neither party is yet ready to back openly the increasing secularism of Irish young people.

Voters must choose instead between the differing styles and approaches of the party leaders, Prime Minister Charles Haughey of Fianna Fail and Fine Gael leader Garrett Fitzgerald. The much smaller Labor Party would be involved in government only as a coalition partner with Fine Gael if neither of the two larger parties wins a majority of seats in the parliament, the Dail, in the proportional-representation voting.

Haughey, a short, compact man with a square chin and angular features, is a charismatic populist who has campaigned primarily on Fianna Fail's record as governing party for all but 10 years since 1932 and his personal identification with Irish nationalism.

The son-in-law of a celebrated prime minister, Sean Lemass, Haughey is a self-made millionaire who has held several Cabinet positions in previous governments. He won a bitter internal party battle to become Fianna Fail leader and prime minister in December 1980 after his predecessor, Jack Lynch, resigned.

It was the culmination of a long political comeback for Haughey following his acquittal a decade ago of charges that he and other Fianna Fail politicians were involved in gun-running for the outlawed Irish Republican Army in Northern Ireland.

As prime minister, Haughey has been best known for his efforts to negotiate with British Prime Minister Margaret Thatcher a closer relationship between Britain and Ireland that Haughey has contended could lead to a solution of the sectarian problem of Northern Ireland.

Haughey has been silent on what he would do about the economy after the election. Sources inside the government hint that if he wins, Haughey will feel free to impose possibly unpopular austerity measures to reduce the government debt and fight inflation. He has been criticized by opponents and the press for avoiding this so far despite his own contention shortly after becoming prime minister that "we are living away beyond our means."

Fine Gael leader Fitzgerald has emphasized his background as an economist by presenting a detailed plan for expanding the economy. A genial, burly man, Fitzgerald is as approachable and talkative as Haughey is aloof and close-mouthed.

Fitzgerald's economic plan consists primarily of a combination of income tax cuts, sales tax increases and curbs of government spending similar to the economic program that won Thatcher election in Britain in 1979. The difference is that Fitzgerald also promises more social benefits and assistance to industry.

But Fitzgerald has been as vague as Haughey when challenged on how he expects to cut government spending or what the effect on already large budget deficits would be of cutting the basic income-tax rate from 35 to 25 percent.