Teamsters President Jackie Presser, who escaped prosecution last summer when the Justice Department dropped a payroll-padding case against him, faces the prospect of renewed federal charges as early as next month -- about the time he is expected to be reelected head of the nation's largest union, it was learned today.

The decision to renew its pursuit of the leader of the 1.7 million-member union represents a dramatic turnaround for Justice Department officials on the politically sensitive case. Only nine months ago, the department vetoed a recommendation by a federal organized-crime strike force to seek Presser's indictment on labor fraud charges.

An internal Justice Department investigation into why that indictment was blocked has concluded that officials who made the decision were misled by what are now considered false statements from Federal Bureau of Investigation agents about their dealings with Presser as an informant, according to several sources familiar with the case.

It was also learned that the FBI had secretly given Presser $2,500 a month for an undetermined period for providing information about organized crime and other matters. Details of the payments were contained in testimony heard by a federal grand jury considering the case in Cleveland.

The payments were handled at FBI headquarters in Washington, D.C., and were treated as highly sensitive information because of Presser's status as a "top-echelon informant," one source with knowledge of the arrangement said.

The allegedly false statements made by FBI agents, under scrutiny by a federal grand jury in Washington involve whether the agents had sanctioned Presser's giving hundreds of thousands of dollars in union payments to "ghost employes" as a way of enhancing his credibility with mobsters.

The purported employes performed no work for the Teamsters and had reputed organized crime ties.

The case is particularly sensitive from a political standpoint because Presser has been President Reagan's sole supporter among major labor leaders. FBI Director William H. Webster and other officials, however, have said that they are satisfied that politics played no part in the handling of the Presser investigation.

Initially, after a three-year inquiry, a federal strike force investigating organized crime recommended that Presser be indicted on fraud charges involving the payroll-padding scheme. Last July, however, after an 11th-hour appeal by Presser's lawyer, John R. Climaco, Justice Department officials rejected the recommendation -- and the Presser investigation was ended.

Climaco, in a meeting with Deputy Assistant Attorney General John C. Keeney, said that Presser had the FBI's blessing in making the "ghost employe" payments and named some of the FBI agents allegedly involved.

Climaco, now the Teamsters' general counsel, and chief union spokesman Duke Zeller did not return calls today about the case.

After Climaco's meeting with Keeney, at least three FBI officials who had served as control agents, or "handlers" of Presser, signed affidavits that supported Climaco's contention that the agents sanctioned the "ghost employe" scheme. It is those statements that investigators have deemed false, clearing the way for the original charges again to be sought against Presser and others.

The Justice Department was led to revive its case against Presser by evidence indicating that Presser did not in fact have FBI approval for his actions, according to government and nongovernment sources. The new evidence was turned up when questions were raised about the decision and the FBI and Justice Department launched an investigation into the matter.

As a result, some agents may also be charged with making false statements in the course of an official investigation, according to sources.

Any charges against FBI agents or Presser would force the bureau to break its silence on the Teamster leader's service as a government informant because that would be a central element in either case.

Sources said that they believe that the agents, in making the allegedly false statements, were motivated by the need to maintain confidentiality and "loyalty to the bureau." Informants are a major -- if not the most important -- resource for the FBI.

Presser is seeking reelection to a five-year term at the Teamsters convention May 19-23 in Las Vegas. Labor Secretary William E. Brock III is scheduled to address the union.