Associate Attorney General Rudolph W. Giuliani yesterday charged that a report by the General Accounting Office criticizing the administration's war on illegal drugs contains "any number of mistakes" and was leaked prematurely.

Giuliani said GAO investigators failed to talk to the key law enforcement personnel running the South Florida Drug Task Force, which has served as a model for the nationwide network of federal drug and organized crime task forces that are being set up this month.

The GAO report charged that federal law enforcement agencies are antagonistic toward one another and sometimes fail to cooperate, or to prosecute drug traffickers once they are arrested.

The report also alleged that arrest figures from south Florida are inflated because two agencies on occasion claim the same arrest.

Giuliani said that coordination among the agencies and arrest and conviction records are much better in south Florida than those reported by the GAO.

The report found that the administration has spent $66 million in less than a year on the south Florida task force while only $127.5 million is budgeted for 12 other task forces covering the rest of the country.

"I don't know the answer to that," Giuliani said. "I've never really estimated it."

Giuliani called the GAO report "simplistic," and said it had failed to address adequately the major changes made in the past year by the administration. FBI agents now are allowed to work on drug cases along with agents of the federal Drug Enforcement Administration.

He added that if it had not been leaked to the press before its publication date Justice would have had time to respond to GAO and correct the mistakes.

Giuliani charged that the report was released "prematurely and in violation of GAO rules and the law" by Sen. Joseph R. Biden Jr. (D-Del.) in an attempt to persuade President Reagan to sign a crime bill containing a provision, proposed by Biden and Sen. Dennis DeConcini (D-Ariz.), to establish a national "drug czar" to coordinate federal drug enforcement.

The Justice Department, which has strongly opposed the drug czar concept, has argued not only that it would create an extra layer of bureaucracy, but also that the bill is so poorly worded that the drug czar could order any government agency, including the Pentagon, to perform any drug enforcement function he chooses, regardless of other priorities.

Giuliani would not say what recommendation the department has given the president, but department sources have said Reagan has been asked to veto it. The president has until Jan. 14 to decide whether to sign the bill.

Giuliani, calling it a "poor way to use the GAO," charged that Biden released the report, which calls for more coordination in the fight against drug trafficking, to try to convince Reagan of the need for a drug czar.

Biden could not be reached for comment. Giuliani said he did not know where Biden obtained the report.