At a downtown restaurant in Rome known for its thick T-bone or fiorentina steaks. Italy's minister of industry, Carlo Donat-Cattin, sat lunching with his usual cronies and discussing - between bitch - tchnical ministerial matters.

At the next table, two men who appeared to be meat wholesalers talked about the quality of their steaks and spoke of union problems in their plants. Across the room, a trade unage cabinet has lasted 10 months - about whether anti-semitism exists in Italy.

The restaurant was full and the hum of voices was load. But except for one table of journalists, there seemed to be little or no talk of the current political crisis, the topic that might have been excepted to be on most Italians' mind.

THE FACT IS that 30 years of frequent government changes - the average cabinet has lasted 10 minths - have left many Italians indifferent and bored by the workings of complex party relationships.

By now the word "crisis" is probbly the most overused word in the Italian language.After centuries of political intrigue, decades of inefficient and unresponsive government, and years of undiluted pessimism, many Itallians appear convinced that la rita continua (life goes on) - it really doesn't matter how the present governmental deadlock over whether the Christian Democrats should give the Communits a greater role in government works itself out.

"Communists, Christian Democrats. For me it's six of one and half dozen of another," said a blue-overalled mechanic taking time out for a cup of coffee. Turning back to his co-workers, he joined in their boisterous discussion of why the Italian national soccer team had been defeated, 2 to 1, by the Spaniards.

In a Roman sauna, a group middle-class women talked about diets and about the unclear-powered Soviet Cosmos satellite that came down in Canada. Two teen-agers awaiting their turn in a neighborhood grocery store discussed a new fingernail polish.

Several customers in a pharmacy in the Trevi fountain Piazza commiserated about the mild but persistent flu that has stricken many Romans.

In the network of narrow shopping streets between Piazza di Spagna and Via del Corso, shoppers took advantage of the January sales and complained about continuing inflation. At the premiere of a Neopolitan tragi-comedy at Rome's Teatro Argentina, both Communist intellectuals and affluent furlcad signore had eyes mostly for a tall blonde in a completely transparent blouse.

INTEREST IN POLITICS is not entirely dead. At the Trevi and Roxy theaters in central Rome, a new, satirical documentary called "Go, Italy," about the ruling Christian Democratic Party and its seemingly immortal leaders in drawing crowds.

"But despite the fact that three is a good possibility that a breakdown in political negotiations will lead to new elections, interest in the government crisis has warned sharply," said a close aide of one of Italy's most powerful Cabinet ministers.

The average Italian is much more concerned about bread-and-butter matters, he said, than the polotical complexion of the new government.

Thus one topic on many people's minds is a new law requiring all working Italians to have a "Codice Fiscale," the equivalent of an American Social Security number, by Jan. 31.

Eager to avoid heavy fines, applicants are forming long lines outside the city's main tax office. In a country where tax evasion has been the rule rather than the exception, many Italians have been thrown into a panic by the continuing crackdown odered by Finance Minister Flippo Maria Pandolfi.

Now that salaried employees all have their taxes automatically with held from their paychecks, Pandolfi has been trying to catch up with the vast ranks of the self-employed.

Italians will now be required to present their codice fiscule for most official transactions, including apartment leases and car sales, and a morning visit to the tax office lines showed that most conversations dealt with ways of avoiding Pandolfi's new system of cross-checks.

Another subject of corcern here is the continued lack of small change, and the controversial private mini-checks that many banks have issued to make up for inadequate coin production by the mint.

Most of the mini-checks for tiny sums like 50, 100, or 150 lire (6.12 and 18 cents) are now in such ragged conditions that signs have been going up on cash registers all over the city stating that they will no longer be accepted.

Last month, the mint finally produced a much-heralded trial series of 200-lire coins, none of which has ver appeared in circulation. Most of them were snapped up by mint employees, Cabinet ministers and VIP's and are now being valued by coin dealers at about $250 each.

NATURALLY. HOWEVER, the biggest bread and butter question is that of growing unemployment. Flagging production has led many major plants to consider lay-offs, and more than a million recent graduates are vainly looking for their first jobs.

High unemployment among Italy's youth is thought to have contributed to the formation of many far-left groups that tolerate or support the mounting terrorism in this country. Even more, it has alienated many Italians from a political system they simply do not trust.

"What difference does it make which parties are in the government," asked a bearded student. "Our politicians care about power, not about helping Italy and Italians get out of their present mess."