Spanish Socialist leader and Premier-elect Felipe Gonzalez today unveiled a moderate government program emphasizing that Spain's economic difficulties give his future administration narrow room for maneuver.

Gonzalez, whose Socialist Party captured 202 seats in the 350-member Congress in elections last month, was addressing the legislature at the start of a two-day debate on a motion of confidence in his rule. The outright Socialist majority ensures that the 40-year-old former labor lawyer will be sworn in by King Juan Carlos later this week.

Echoing his party's key election slogan that socialism represents "change," Gonzalez told the legislature, "On this historic and decisive day, change starts now." The content of his address, however, suggested otherwise.

In an 80-minute speech, Gonzalez mentioned the word socialism just once as he itemized the sober economic realities. Unemployment, he said, represents 16 percent of the active working population, inflation is running at 15 percent, the balance-of-payments deficit has risen sharply and the public-sector deficit constitutes 5 percent of the gross national product.

The Gonzalez recipe for dealing with the economy appeared to be a conservative approach. He promised austere public spending and tightened monetary controls that he said would reduce inflation next year by three percentage points. Gonzalez's forecast of a 2.5 percent growth rate in 1983 was in keeping with a recent projection by the Bank of Spain.

The Socialist leader repeated his election pledges that his government would create 800,000 jobs during its four-year mandate. The promise to reduce unemployment, together with the pledge on inflation, constitute the main credibility tests for the Gonzalez government.

The outgoing centrist administration, which has governed since democracy was restored after Francisco Franco's death, had promised to create 350,000 jobs this year while holding inflation at 12 percent. In fact, inflation exceeded that level and unemployment topped 2 million, according to the latest government figures.

Gonzalez coupled his economic program with warnings that his government would be tough in prosecuting tax frauds and keep a sharp watch on any potential flight of capital. "There are no easy solutions," he said of the country's financial difficulties, "only hard work and tenacity."

The Socialist leader kept to his moderate pitch when he outlined foreign policy, saying it was enshrined in "Spain's presence in the Western world, whose values we share and defend."

In a brief reference to Spain's defense treaty with the United States and to NATO membership, Gonzalez said both would be reexamined "in the light of national and international dialogue which such important decisions require."

Gonzalez said the treaty, signed last June by the outgoing centrist administration and still awaiting ratification, would "be examined with all attention."

The Socialists had pledged during the election campaign that they would stage a referendum on the NATO issue but Gonzalez avoided specifying the details of such a plebiscite. Socialist spokesmen in recent days have emphasised that a referendum on NATO is not a priority but that the new government intends to keep its promise to initially freeze negotiations in Brussels to join the NATO military command structure.