Short of supplies and transport, anti-Sandinista rebel forces recently have reduced the scope and level of their three-year-old guerrilla war.

U.S. and rebel officials have attributed the reduction in rebel activity mainly to lack of funds, which apparently is catching up with the main guerrilla force nine months after Congress imposed a ban on CIA financial aid.

Interior Minister Tomas Borge said the shift also reflects recent successes by the Popular Sandinista Army in driving rebel forces northward toward the border region with Honduras and, for many, across the border into camps within Honduras. In a reflection of this, Defense Ministry reports have shown a clear drop in the number of incidents in recent weeks.

"This favors us, because the war is going away from the interior of the country and toward the border," Borge said in an interview, referring to the decline of rebel activity in the more populated and economically important central zone.

"But at the same time, it implies a certain risk, because a border war is always dangerous for the implications it might have for a neighboring country, in this case Honduras. We will try to be very careful not to give any pretext that could provoke an incident."

U.S. officials in Honduras have expressed similar fears that more regular rebel crossings of the border area raise the risk of clashes between Honduran and Nicaraguan troops in the frontier hills.

At the same time, the increase in rebel troops on Honduran territory has intensified nervousness within the Honduran armed forces over that country's role in aiding the U.S.-backed insurgents.

The Honduran government protested sharply when 17 Nicaraguan soldiers drove across the border and were arrested Tuesday in what Managua said was an accident. But an aide to Borge expressed confidence that the soldiers and their military trucks will be returned without major complications.

Borge estimated that 6,000 to 7,000 guerrillas from the main rebel group, the Nicaraguan Democratic Force, gathered recently in camps in southern Honduras near the mountainous border with Nicaragua. This is up sharply from the number late last year, when most of the rebels were reported inside Nicaragua ambushing Sandinista Army and government vehicles and agricultural cooperatives.

U.S. and rebel officials have put the number inside Honduras at 5,000 to 6,000 from a total strength estimated by rebel officials at more than 12,000.

Miskito, Sumo and Rama Indian rebels in the Atlantic coastal region and Eden Pastora's independent anti-Sandinista guerrillas along the border with Costa Rica have another several thousand armed men. But they have been largely inactive for a number of months because of a lack of supplies, their leaders have acknowledged.

Borge said the Popular Sandinista Army has done better against the Democratic Force rebels in recent months because it has adapted to guerrilla tactics and increased the number of special units.

Sandinista forces also have put special emphasis on striking at rebel supply lines to prevent guerrilla troops from remaining for long periods inside Nicaragua, he explained.

Rebel leaders have told visitors to their camps in Honduras that they have had trouble resupplying forces inside Nicaragua. But they attributed this to lack of consistent ammunition deliveries and adequate maintenance of aircraft used to make drops. This, they explained, was a result of money shortages.

Adolfo Calero, the chief Democratic Force political figure, said the organization has raised more than $5 million since the congressional fund cutoff last spring. But aides of the rebel military chief, Enrique Bermudez, said they have been unable to continue supply drops at the same pace as when CIA funds and logistic help were available.

After barring further CIA aid a year ago, Congress voted last fall to make $14 million more available to finance rebel forces, but only on the condition that the funding be approved this spring in another vote.

On Thursday, President Reagan proposed that the $14 million be used only for humanitarian assistance should Nicaragua begin talks with the rebels. Managua rejected this approach, and Congress is to vote on the money this month.

Before the cutoff last spring, the CIA had provided rebel forces with a sum estimated by congressional sources at $80 million since 1981.