The leading Lebanese Christian party and the Palestine Liberation Organization both held press conferences today and accused each other of training Germans as terrorists.

The Maronite Christian Phalange Party, bitter foes of the PLO, presented two West German men who said they were part of a group of about 30 neo-Nazis being trained as terrorists in a PLO camp from which they escaped 11 days ago.

The Phalangists claimed that information supplied by the two led to the arrest in West Germany of three neo-Nazis, including the man who recruited them.

The PLO first denied the charge and then tonight held its own press conference at which they produced two other West Germans who said they had received military training from the Phalange but later joined the Palestinian cause.

When asked at the press conference what the symbol of the Phalange Party is, however, they drew two crossed swords, raising doubts among observers about their account. The actual symbol is a cedar of Lebanon and observers here know of no crossed-sword insignia for the Phalange militias.

Nonetheless, PLO spokesman Mahmud Labidi accused the "information services of the Zionist entity [Israel] and their collaborators of the Phalange, supported by American information and mass media," of trying to label the PLO as terrorists.

"They want to stop the growing understanding and growing success that the PLO has achieved on the international level, especially among the European nations," he said.

The two Germans produced by the Phalange -- Walter-Ulrich Behle, 22, and Uwe Johannes Mainka, 24, said they were recruited for terrorist training in West Germany by Karl-Heinz Hoffmann.

Hoffmann, who founded a neo-Nazi organization that was banned in West Germany last year for advocating the overthrow of the government, was arrested in Bavaria this week with a woman and another man who was reported to have received military training in Lebanon.

Behle said he and Mainka came to Beirut with about 30 others last October to receive training in weapons and explosives.

Instead of receiving training, Behle said, the men spent most of their time repairing PLO trucks and cars and putting up buildings and antiaircraft shelters. He said they were given no political indoctrination by the PLO.

"We were working there and some days we would get shooting practice," he said, adding that it was far less than the extensive training in explosives and special weapons he had expected.

He said he and Mainka sneaked out of the camp about 3 a.m. on June 14 when everyone else was asleep and made their way to the Christian side of Beirut. Once in east Beirut they were taken into custody and held until now by the Phalange organization, he said.

Behle said he was not disturbed by the leftist ideology of the PLO. "I only wanted to get my military training there and that was important to me," he said.

Amin Hindi, a PLO security official, said Behle and Mainka were among 10 West Germans who had been picked up by the PLO in Beirut, taken to a camp and put to work there. He ignored questions as to why the Germans had been confined and why they had not been turned over to Lebanese authorities.

The two West Germans produced by the PLO, who gave their names as Hans Dieter Eckner, 31, and Ulrich Bauer, 21, said they had been encouraged in Germany by a Lebanese Christian to train with the Phalange militia in Beirut. They said they arrived here early in 1980 and were taken to the Phalange training camp in east Beirut.

In January, they said, they were captured by Palestinians. At the camp where they were held, they said, they knew Behle and Mainka by their Arab code names.

Eckner and Bauer denied being neo-Nazis or terrorists and said they belong to Franz Josef Strauss' Bavarian-based Christian Social Union.