The United States has been unable to begin a $15 million cross-border humanitarian aid program for the Afghan resistance movement because of a lack of agreement with Pakistan over how it should be organized, according to U.S. officials.

After six months of planning and discussions with the Pakistani government, the program "hasn't been put into operation . . . because the Pakistanis are unable to agree among themselves how to do it," an Agency for International Development official said.

The proposed program -- the first to be undertaken by AID inside Afghanistan -- is considered a delicate operation within the agency because it involves setting up health, education and agricultural projects inside rebel-held areas that are constantly under Soviet or Afghan bombardment.

The projects would be run by Afghan rebels or European private groups already working in rebel-held areas, rather than AID officials or private American volunteers.

A Pakistani Embassy spokesman said the embassy had no information regarding the proposed program or the reasons for the reported delay in starting it.

Congress appropriated an initial $15 million annually for humanitarian assistance to the anticommunist Afghan guerrillas, beginning this fiscal year. This aid is in addition to the nearly $500 million in secret military aid allocated by Congress for the Afghan resistance struggle. No interruption in the delivery of U.S. military aid, which includes ground-to-air Stinger missiles, has been reported.

U.S. officials say that implementation of the new AID program has been delayed by the establishment in Pakistan last December of a new civilian government led by Prime Minister Mohammed Khan Junejo, who has been reviewing the policies of the previous military government of President Mohammed Zia ul-Haq toward the Afghan resistance.

"The holdup is due to the change of governments," one AID official said. "They haven't seen their way to working out a specific arrangement we can all agree to."

Another AID official said the Junejo government wanted to have its own organization supervise all private volunteer organizations and their many aid programs for the Afghan resistance being administered inside Afghanistan.

As early as the spring of 1985, AID began developing plans for a long-term, cross-border aid program to help the Afghan rebels maintain a civilian population inside rebel-held zones.

The agency has sent teams to design projects that would provide basic health services as well as specialized projects for war-related injuries, paramedical training, expanded primary schooling, distribution of foods and goods in "liberated zones," and agricultural schemes aimed at increasing the rebels' ability to feed themselves.

AID allocated $8 million in short-term medical and emergency food aid to the Afghan resistance during fiscal 1985 through U.S. and European private volunteer organizations and the International Red Cross. AID officials said one way to distribute the $15 million in new funds would be simply to funnel the money through the private groups.