The main Nicaraguan rebel movement is seeking to issue interest-bearing bonds in the United States and abroad as a way to raise money for its struggle to overthrow the Sandinista government in Managua, according to insurgent leaders.

The bonds and other financial instruments would be aimed mostly at investors who for ideological or national reasons support the rebel cause, rather than the general investing public, they said.

The bonds are to be part of an overall rebel fund-raising effort that has generated approximately $5 million here and abroad since CIA funding stopped on congressional orders last June, according to Adolfo Calero, primary leader of the main anti-Sandinista group, the Nicaraguan Democratic Force (FDN by its Spanish initials).

A spokesman for the rebel movement explained the new funding program by drawing an analogy to Israel Bonds, which are sold widely primarily to Jewish supporters of Israel living in the United States and Western Europe.

Bosco Matamoros, the FDN's Washington-based spokesman, said in a telephone interview that the organization is considering bonds, guaranteed loans and limited-responsibility partnerships. The FDN or a corporation founded by it would assume responsibility for the principal and "a reasonable rate of interest," he said.

Saying the FDN was weighing various combinations of the three financial instruments, Matamoros did not explain from what source the organization would draw to pay interest on the proposed bonds. He said they would be relatively short-term and probably limited to informed investors whose motives were political as much as financial.

"What is the motivation for Israel bonds?" he asked. "Ours will be the same. We do not necessarily have to make it a very broad public issue."

Calero, interviewed in Miami, said a Washington law firm hired by an anonymous benefactor is taking the necessary legal steps to begin offering the bonds for sale. Both he and Matamoros refused to name the firm.

A Justice Department spokesman, John Russell, said such bonds would encounter no problems with the Neutrality Act, which bars actions or conspiracies on U.S. soil aimed at overthrowing the government of a country at peace with the United States. Depending on the type of fund raising, he added, it could fall under some requirements for registration as a foreign agent.

Russell said by telephone that a law firm, which he did not identify, had made inquiries at the Justice Department on behalf of the Nicaraguan rebels.

Calero reiterated earlier denials that the Reagan administration is sidestepping the congressional fund cutoff by funneling money to the Nicaraguan Democratic Force through such countries as Honduras, El Salvador or Israel. Several congressmen have expressed suspicion this is taking place despite administration denials.

A source with close connections to the rebel movement said, however, that the Honduran military has in the past supplied ammunition to the anti-Sandinista guerrillas, whose main staging camps are on Honduran territory. El Salvador has made its military airport at Ilopango available for rebel flights to air drop supplies inside Nicaragua, according to published reports.

The issue has come to the fore again as administration officials press for renewal of the CIA funding, estimated by congressional sources at $80 million since 1981. Langhorne Motley, assistant secretary of state for inter-American affairs, told a House subcommittee Tuesday that continuing the ban would be a serious mistake.

Congress appropriated $14 million for the rebel movement last fall for fiscal 1985 but barred expenditure of the funds pending another vote this spring. The effect was to maintain the freeze on the aid.

Calero estimated his group's expenditures at $600,000 a month. Because of discounts from sympathetic suppliers and donations in kind, he added, the actual outlay often is less.

For example, he said the rebel organization just bought uniforms at $5 apiece, significantly below the going rate. Moreover, he has said previously a military supplier opened a $900,000 credit line for equipment purchases. Calero has declined to identify the company.

Calero, who managed the Nicaraguan Coca-Cola Co. before going into exile, said most FDN funds have come from a relatively short list of large-scale donors since the congressional cutoff, including "governmental sectors" abroad and an American businessman who he said was paying for legal preparation of the bond issue.

Calero declined to identify the "governmental sectors" or the businessman. Such mystery, combined with assessments that a guerrilla war with more than 10,000 irregulars under arms requires steady financing and predictable lead time for munitions purchases, has fueled the suspicions in Congress about backdoor CIA financing, a congressional source said.