For the second time in less than four months, a battle among the turbulent state of Africa has turned up a new face among the interested world spectators.

The face is that of East Germany - a steadfast Warsaw Pact ally of the Soviet Union that is becoming increasingly involved in activities in black Africa below the Sahara.

In May. Zaire expelled East German diplomats and suspended relations with the European country, accusing East Berlin of supplying arms to anti-government rebels in Shaba province.

Today, as the undeclared war between Ethiopia and Somalia continues in the Ogaden desert observes in both capitals are noting that there seem to be a number of East Germans present.

Although Western attention continues to focus on the major role of Cuba and the Soviet Union in Africa. East Germany has made inroads into several of the more revolutionary states in the past two years. Western specialists rank it as the third most influential Communist power in the area.

East Germany quickly recognized the new Popular Front government in Angola in 1975 and is well established there, reportedly with several hundred persons in the country and the largest presence behind Cuba and the Soviet Union.

In Mozambique, East Germany has the largest embassy staff of any EastBloc country, including the Soviets.

In recent months, its presence and role has been expanding most noticeably in the Horn of Africa, expecially in Ethiopia.

Many of the East German activities are traditional and open such as development, technical and humanitarian aide programs, trade missions and trade union and student exchanges.

In many places, the East Germans also can carry out policies for the Soviets where an increased Russian presence might be sensitive or unwelcomed.

For a country that for much of its post-war years has had no international image. Africa's developing stakes are an attractive targed for East German foreign policy - a place where it can gather official recognition, lay the groundwork for new embassies to be set up in East Berlin, complete more evenly with West Germany, and help undermine the Bonn governemt's efforts and image in Africa.

There are, however, increasing signs that East German support for left-wing liberation movements is moving more frequently into more volatile, yet generally well-camouflaged, forms of aid - small arms supplies, military advisers and internal security training.

Though the East Germans "are extremely discreet about such thing" and information is hard to come by specialists on the subject estimate that the East Germans had only about 100 military advisers and technicians in sbu-Sahara Africa in 1973. Today, the estimate the figure is between 300 and 400.

The Soviet presence is still much larger. The Soviets, sources estimate, went from 1,000 military adviser-technicians in 1973 to more than 7,000 now. Cuban military presence in black Africa jumped from an estimated 400 to more than 14,000 troops, largely in Angola.

East Germany's growing involvement and the likelihood of a policy coordinated with Havana and Moscow was also highlighted in april when Cuban President Fidel Castro stopped in East Berlin before going on to Moscow after a tour through African and Arab countries.

Though the East Germans denied Zaire's charges of providing arms to rebels, reliable sources say there was evidence of such weapons and that the development was significant because it was a new role for the East Germans. The small arms supplies flowing into such areas have been dominated mostly by Czechoslovak weapons.

Sizeable numbers of East German military specialsists are said to be training forces, including pilots, in Angola, with smaller numbers in the Congo, Somalia and Mozambique.

In Mozambique and Ethiopia, the assistance is said to be mostly organizing internal police forces, supplying them with arms and teaching them how to use vehicles and communications equipment. "The distinction with the military gets very blurred," one official said.

The East German interest in strategically-located Somalia and Ethiopia is viewed as purely political, as opposed to interests in central and southern Africa where important trade and raw materials factors are involved.