Both reported to and consulted with North frequently by phone and at North's office in the Old Executive Office Building next to the White House, the officials said.

"That's how the system worked, " said one official who monitors contra activities. "Owen was the messenger boy and Gen. Singlaub the military commander, chief fund-raiser and arms adviser and broker."

Owen refused to be interviewed.

Singlaub, in an interview earlier this year, acknowledged being in contact with North but denied receiving instructions from him. Singlaub also acknowledged having raised funds for the contras to buy weapons, but said transactions were made outside the United States to avoid violating the 188-year-old Neutrality Act.

Singlaub said he also advised the contras on types of weapons they needed.

A knowledgeable contra official said Owen was North's "gofer" and kept in touch with rebel leaders in Honduras and Costa Rica.

An administration official intimately familiar with contra affairs said he had been instructed by the NSC to refer to Owen anyone offering supplies or funds to the contras during the time of the prohibition.

'BAD ORGANIZATION'

The contra official said Owen also had been assigned the role of organizing a southern front that would be supplied from Costa Rica. But the contra said the project never prospered because of "bad organization."

Rebel officials said that since last summer the CIA has gradually widened its involvement by paying for the travel and living expenses of contra leaders and financing their propaganda projects. The increased CIA role, the rebels said, has displaced the NSC, diluting the council's influence.

Administration officials said that since last year, the CIA has secretly funneled between $1.5 million and $3 million to the contras' umbrella group, United Nicaraguan Opposition (UNO), to pay rebel officials and supporters, and to open offices in Western Europe and Latin America.

A rebel official said CIA officers also have intervened in internal contra political disputes in a bid to bring about unity in the fractious anti-Sandinista movement.

The rebel said the CIA played a key role in persuading Eden Pastora's six senior commanders to desert their leader in May after he refused to ally himself with UNO. Pastora later gave up his fight and sought political asylum in Costa Rica.

Rebel officials said the CIA's main goal now is to consolidate a totally unified contra alliance and prepare it for a major offensive against the Sandinista government if and when Congress approves Reagan's $100 million proposal for military and logistical aid.

If Congress approves the package as the administration has proposed, all restrictions on CIA involvement will end and the agency again will be able plot the contras' military moves.