Falling oil prices and a move by petroleum-producing nations to cut output have rudely surprised Venezuela at a time of painful economic austerity and raised questions about its ability to meet a demanding new payment schedule for its foreign debt.

As ministers of the Organization of Petroleum Exporting Countries prepare to meet Monday to consider deep production cuts to bolster sagging world prices, Venezuelan officials have struggled to convince their jittery public that a new reduction in the country's vital oil revenues will not produce a crisis.

"There is no catastrophe here, nor is the country going under," President Jaime Lusinchi declared this week. Top officials have maintained that an unexpected surplus in export revenues this year, government financial reserves and conservative estimates of oil earnings built into the national budget could allow Venezuela to absorb a substantial loss of production or prices with relative comfort.

Officials here concede, however, that the move by Norway, Britain and OPEC member Nigeria to cut light oil prices last week shocked a nation that depends on oil for 95 percent of its export earnings and more than 70 percent of government spending.

"We are always worried about the OPEC system; inevitably we are always worried," said Simon Alberto Consalvi, a high-ranking government official. "Any oscillation of the oil market has to affect us."

Experts outside the government have warned that a sustained reduction of OPEC production or prices could destroy Venezuela's attempts to rebuild a long-stagnant economy and endanger a newly negotiated plan for payment of the country's $37 billion foreign debt.

"We should be prepared because Venezuela's capacity for debt payment is going to be affected," former energy minister Humberto Calderon Berti said at a press conference. He suggested that the loss of petrodollars could force Venezuela to slash spending or devalue its currency, provoking a recession or inflation.

Bankers and most independent experts, pointing to predictions that the world oil market could rebound within a few months, say such gloomy speculation is not justified yet. Government and opposition economists agree, however, that the new crunch in oil prices has struck Venezuela at a bad time.

"It came as a surprise," said Alberto Valero, a top Energy Ministry official, "and so in some sectors there has been a tendency to panic."

Since taking office in February, Lusinchi's social democratic government has been struggling to adjust Venezuela's economy to the 25 percent decline in its oil revenues since 1981 and the pressure for payment of its debt, which is the fourth-largest in Latin America after Brazil, Mexico and Argentina.

The petroleum slump, worldwide economic recession and previous government austerity measures have halted economic growth for this South American democracy of 15 million since 1979. Following OPEC price cuts last year, Christian Democratic president Luis Herrera Campins devalued the Venezuelan currency, reduced imports by half and allowed unemployment to rise to approximately 20 percent.

Facing election year pressures, Herrera cushioned the impact of Venezuela's reduced income by maintaining high government spending, implementing price controls to limit costs of imported goods and delaying both loan payments and the renegotiation of the debt.

Lusinchi's administration has thus been left with the unpleasant task of raising prices for basic internal consumption, holding workers' wages below inflation and trimming government spending to make room for the $4.4 billion in principal and interest Venezuela has agreed to pay on its debt next year.

Last month, the government submitted an austere 1985 budget to the National Congress that will reduce spending in real terms by up to 7 percent, continue to hold salary increases below inflation for a million government employes and devote about 35 percent of revenues to debt payments.

Until now, the government has hoped that its belt-tightening measures could be flexible enough to shield the country from the sharp recession undergone by such countries as Brazil, Mexico and Peru in seeking to pay their debts. Blessed with abundant foreign reserves of more than $12 billion and spared from having to seek fresh loans from reluctant bankers, Venezuela is the only Latin American country with debt problems that has been able to avoid accepting a formal stabilization program from the International Monetary Fund.

So far, Venezuelan officials have avoided large layoffs of state workers or dramatic hikes in controlled prices, and have targeted resources on key sectors such as agriculture and the construction industry in an attempt to promote at least a partial economic recovery. Although gasoline prices have doubled, a gallon of gas in auto-choked Caracas still costs only 25 cents.

Government officials say a long-term agreement with banks last month on about $20 billion in government debt has essentially resolved the country's international financial problems. The agreement stretches payments out over 14 years at an interest rate similar to that obtained by Mexico in a long-term agreement in August. It provides for annual payments equal to about 30 percent of current oil revenues.

"Our debt problem has been resolved," Finance Minister Manuel Azpurua said flatly. He predicted in an interview that the Venezuelan economy could begin to grow again "sometime in the course of 1985."

Officials concede that their economic strategy remains fragile. Opposition leaders and some independent observers have predicted that Lusinchi's administration will not be able to stick to its tight spending guidelines. Restless unions, although largely controlled by members of the government's Democratic Action party, already have grown restless over wage controls and many appear likely to oppose the scant increases planned for next year.

Bankers and economists point out that the debt agreement has not been completed yet and could be blocked by lingering political and technical problems. The most important of these concern roughly $1 billion in loan arrears owed by Venezuela's private sector.

Under these circumstances, the new oil price crisis is viewed by both government and business leaders as a dangerous new weight in the country's fragile economic balance.

"At the very least, it will leave us more vulnerable," said Pedro Palma, an economist who has formed part of the government's debt renegotiation team. "It will be difficult for us to face anything else that happens."