Italy's restaurants turned off their stoves today in a nationwide protest against new measures to prevent tax evasion, leaving many Italians and foreign tourists to go hungry.

The strike by tens of thousands of restaurant owners, dubbed the "wild saucepan" by Italian newspapers, left office workers nowhere to go for lunch.

In Rome, grocery stores, were crowded with disgruntled bureaucrats who, forced to do without pasta, were ordering take-out sandwiches and beer. In Naples, restaurant customers braced themselves for an indefinite work slowdown. Many owners have vowed to serve only spaghetti with tomato sauce, mineral water and omelettes. The southern city's pizza makers have also said that they will prepare only a "poorman's pizza" seasoned with tomato and a litle oil.

The Association of Italian Restaurant and Cafe Owners called today's strike, and scheduled another for March 1, to protest a law that will require all restaurants, luncheonetts and hotels starting next month to provide their customers with numbered bills stamped by the Finance Ministry.

The restaurant and hotel owners said they oppose the law because it will complicate their accounting. They say it fails to distinguish between large restaurants and those which are only marginally profitable.

But most observers here believe the main reason for the often violent opposition is the reluctance of this highly profitable sector to pay taxes.

According to labor leader Giorgio Benvenuto, the opposition "masks an arrogant desire to continue and infinitum to defraud both the internal revenue service and the consumer."

Finance Minister Franco Reviglio, a well-known economist with ties to the Socialist Party, designed the bill in an attempt to recover an estimated $9.6 billion in upaid value-added taxes. The Finance Ministry responded to today's strike by inserting a large ad in most major Italian papers that said, "Ask for the fiscal receipt: it's the new bill created in the common interest."

The ad explained how the new system will work and described the fiscal receipt as "a step forward toward a more equitable system of taxation."

Tax evasion is a time-honored occupation in a country where centuries of exploitive rulers made taxation synonymous with oppression. A popular proverb says, "Better a dead man in the house than a tax collector at the door."

But since 1974, when tax reform authorized withholdings on wages and salaries, most salaried workers about 80 percent of the total labor force -- have been paying their taxes in full.

Noncompliance in other sectors, however, is still a serious problem. Finance Minister Reviglio recently released government figures showing the restaurant and hotel sector conceals 68 percent of its turnover.

In 1977, according to those figures, 87 percent of the country's hotel and restaurant owners declared an average turnover of only $13,000.

"The figures regarding tradesmen and professionals are equally appalling," said a spokesman, "but we are starting with the hospitality sector because the billing system provides us with a handy instrument."

He pointed out that the government has tried to meet the restaurant owners half way by simplifying the procedures for itemization of the products consumed, and by putting off the application of fines for noncompliance until next fall.

But the restaurants refused to call off the scheduled strikes. They are now asking to be allowed to number their own receipt pads. This could allow a gradual transition to full, or near-full declaration and avoid focusing the Finance Ministry's attention on the extent of past evasion.

"What they want is for tax evasion to be legalized," snapped a communist worker whose taxes are automatically withheld.

But Alvaro, the owner of a popular fish and game restaurant here, insists that opposition to the law is only "to protect our right to free enterprise." He said that if the law goes into effect he will fire his waiters, raise prices, and serve just enough meals a day to give his family a reasonable income.