A resurgence of Mafia-related violence in Sicily that earlier this week took 12 lives in less than 24 hours indicates that Italian authorities are making little headway, despite a police crackdown, in their battle against the island's powerful criminal organization.

Following killings in Gela, Catania and Palermo on Tuesday and Wednesday, Italian police have set up roadblocks and searched known Mafia hideouts and arrested several dozen suspects.

The city's number-two detective, Francesco Pelligrino, said the shotgun "has become the means for resolving every disagreement." The murders were seen here primarily as evidence of a new round of an ongoing gangland war between Mafia families over the flourishing narcotics trade and other rackets.

Last year a raging battle between the so-called "winning Mafia"--the "families" who have known how to adapt their criminal methods to industrialized society--and the old-style "losing Mafia" led to almost 300 murders.

"We can't continue like this," said Elda Pucci, a 55-year-old pediatrician recently nominated for mayor of Palermo by the dominant Christian Democrats, who are seeking to improve their party's corruption-tainted image in the city.

Authorities have attempted a crackdown, as demonstrated by a trial of 75 suspected drug traffickers and a special meeting in Palermo of top magistrates on Mafia-related problems. But the flareup in bloodletting has been seen by some observers as a warning to authorities.

Yesterday in Carini, a small town on the road to the Palermo airport, a magistrate's black robe was found burned in a local judicial office. According to press reports, one of the six visiting magistrates received a threatening letter.

On Tuesday, unidentified gunmen attacked the car of a suspected drug trafficker, Antonino Sorci, 78, killing him and his son. A former lieutenant of Charles (Lucky) Luciano, Sorci was known as Nino the Rich.

A few hours later, two or three armed men burst into a conference of the Romagnolo family, Palermo shoe and leather wholesalers, killing two brothers and the son of one of them, and wounding four others.

Wednesday morning Giuseppe Misuraca, 70, described as a small "boss," was shot dead in an attack by two men on a motorcycle as he stood in the street waiting for his wife.

Following the assassination last September of Palermo's top police official, general Carlo Alberto dalla Chiesa--a killing described at the time as a "mortal challenge" of the state by the Mafia--Italian.

Emanuele de Francesco, head of Italy's civil intelligence agency, was made high commissioner for the fight against the Mafia. He also took dalla Chiesa's place as prefect of Palermo.

Superprefects were also appointed in Calabria and Campania to fight local criminal organizations, and a tough anti-Mafia law was passed that gives the government the power to get at criminals by examining the source of their wealth.

The law has been applied vigorously by Socialist Finance Minister Francesco Forte and in recent months several suspected Mafiosi have had real estate and other property confiscated.

Earlier this week, the prefect of Naples, Riccardo Boccia, announced that a police crackdown involving more than 11,000 arrests in the Campania region in 1982 had slowed the gangland murder rate. During the first three months of this year there were only 60 such murders, compared to 100 in the same period of last year, a report by the Naples prefecture said.

In Sicily, however, the murder rate continues at high levels. Dalla Chiesa's murderers are still at large, and although police have intercepted massive heroin shipments, the impact of the fight against the Mafia appears to be limited.

The drug traffic between Sicily and the United States alone is estimated to bring into Mafia coffers some $700 million per year, minister Forte said recently. During a visit to Italy last November, Attorney General William French Smith described Sicily as "the processing point of perhaps 80 percent of the heroin that enters the northeast United States."

In an interview yesterday with the Rome daily La Repubblica, High Commissioner de Francesco said that 427 financial investigations currently filed with the Palermo judicial office could "suffocate" the local magistrature. But he also expressed optimism that in the long run the new anti-Mafia law would prove effective.

Bank deposits and bond purchases dipped significantly after the law was passed in September. But "those who are now hiding their money will sooner or later have to deposit or invest it and thus come out into the open," he said. De Francesco recently won approval for replacing a system by which suspected Mafiosi were ordered to live in small northern towns. Now they are to be under surveillance in tiny southern communities.

It is argued that the "forced confinement" system allowed the alleged Mafiosi too much freedom, enabling them to set up Mafia businesses, including the profitable kidnaping "industry," in the north.

The high council of magistrates has recommended eliminating jury trials for suspected Mafia criminals, on the grounds that local jurors may be easily intimidated.

But the real problem, de Francesco has said, is how to improve work opportunities on the island so young people will not be enticed by Mafia promises of easy wealth.