About 50 prominent blacks met here yesterday to launch a political lobby they hope will become a major factor in changing U.S. policy toward Africa and the Carribean.

The group, called TransAfrica, released a position paper calling on the United States to cease addressing African nations as "pawns in a game of geopolitical roulette between the major powers", and to formulate its African policies with a focus on the issues Africans, view as critical - majority rule, restructured trade relations and economic aid.

TransAfrica grew out of a 1976 Congressional Black Caucus conference, at which a task force was created to draft and implement a plan for creating an effective domestic Africa lobby.

At that conference, "There was great frustation expressed about the lack of a mechanism to influence U.S. policies toward black African countries," said Richard G. Hatcher, mayor of Gary, Ind., and chairman of TransAfrica's board of directors.

Hatcher said he sees a "direct relationship" between what happens to black Americans and what happens to black Africans.

For example, he said, if the rich mineral resources of South Africa "were in fact controlled by black Africas, as they should be, and the rape of those resources were prevented, many blacks Americans might be in a position to develop an economic relationship with that country in such a way that there would be mutual benefits to both black Americans and black Africans."

In the industrial midwestern city he has run for a decade, Hatcher said, he has noted "an increasing concern" about Africa among blacks "economically secure enough to afford the luxury" of dwelling on questions beyond their own survival.

"I think the fact that that concern has not been pervasive or overriding in the past has been a function of th shutout and distortions of what's going on in Africa by the national media."

He cited as an example current articles on the fighting in Zaire which he said have focused more on the fates of Europeans trapped there in Kolwesi than on the condition of Africans or the political background to the fighting.

Hatcher said his role in TransAfrica will be largely fund-rasing. The group has held fund-raisers in New York, Detroit and Atlanta, all hosted by local black politicians. It plans others for Los Angeles, Boston and Philadelphia in September.

Randall Robinson, TransAfrica's executive director, predicted that the group will reach its goal of a $200,000 budget for this year by the end of September.

So far, he said, between 5,000 and 10,000 donors have contributed. The group concedes that it will have fund-raising problems because it has decided not to accept money from foreign government - in order to avoid having to register as a foreign agent - or from U.S. corporations that do business with South Africa. As a lobby, TransAfrica is not a tax-exempt organiation.

There has for years been an informal "Africa lobby" consisting of interested blacks from the State Department, the CIA, Capitol Hill and private organizations.

Robinson said TransAfrica includes many of the same people, but that "the attempt here is to go well beyond the traditional "Africa people" and try to cultivate a mass political base."

A beginning, he said, is through the black church, "a sustaiming institution in black America . . . with a captive audience" receptive to "moral issues" like majority rule in South Africa.

TransAfrica will be trying, Robinson said, to develop an effective mechanism for lobbying Congress and the administration, to create an information network to black Americans and to build a grass-roots base.

The group is also trying to forge ties with African representatives here. Ambassadors from Nigeria and Zambia have accompanied Robinson to fund-raisers, and Zambian President Kenneth Kaunda told the National press Club Thursday - with Robinson seated on the dais - that black Americans should form a sophisticated Africa lobby.

TransAfrica sounds very much like an effort to create for blacks in America and Africa an organization similar to the "Jewish lobby" which has been so effective in mobilizing support for Israel.

The comparison is one Robinson rejects. "Jews' cultural and other variables are different in our case, and don't have applicability to us," he said. He added that blacks are not as well off as Jews in America, and thus cannot contribute money on a comparable scale, but that blacks do have a numerical advantage that can be translated into votes.

"What we are saying to the administration is that this issue of international affairs is on a plane with our domestic concerns," Robinson said.

The position paper TransAfrica released covered four subjects - economic cooperation, the situation in the Horn of Africa, southern Africa and U.S. relations with the Carribean.