A U.S; trade mission to Africa headed by Ambassador Andrew Young today explored business opportunities in the Ivory Coast, including the possibility of new oil concessions.

American bankers accompanying Young on the seven-nation tour said they were prepared to guarantee U.S. private investments of up to $1 billion in this West African country.

Once considered the backwater of the French West African colonial empire, the Ivory Coast today is regarded as one of the most economically successful and politically stable countries on the continent.

"It is important for American business to get a foothold in Francophone Africa," said Theodore A. Adams, president of Unified Industries, Inc., an electronics company based in Alexandria, Va.

The trip illustrates what is potentially a new phenomenon for American business efforts overseas: the use of high-ranking political official to open doors and ensure a U.S. trade mission's quick access to the top decision-makers of the host government. This has long been done by European and Far Eastern Countries, whose presidents and prime ministers -- eager to improve trade balances -- have often lobbied personnally on official visits to drum up private business for their nation's firms.

Adams, one of 23 U.S. businessmen in the delegation, said Young's popularity in Africa has been instrumental in providing top-level access to African policy-makers. The trip was planned before Young announced his resignation as ambassador to the United Nations over an unauthorized meeting with the Palestine Liberation Organization's U.N. observer, and it is expected to be one of Young's last official acts before he leaves office around Oct. 1.

The Ivory Coast is the second stop on the trip after Liberia. The mission is to leave Tuesday for Nigeria, the second biggest supplier of oil to the United States.

"It is because they like Andy Young that we are able to get to the right people," said Adams. "I accomplished in two days in Liberia what would normally have taken one year," he added after signing a negotiating agreement for the manufacture of computer parts in Liberia.

In Abidjan, officials have expressed an interest in American investments in agriculture, increased oil exploration and mining, production of chemical fertilizers, educational television and tourism.

Paul Gui Dibo, the minister of mines, told D. Truitt Davis, chairman of Consolidated Petroleum Industries, that there were plenty of offshore oil concessions that he could bid on.

"Just submit an application," Dibo told Davis in an hour-long session with several businessmen this morning. Next year, he said, the Ivory Coast will begin production of prime "sweet crude" oil from discoveries made in 1977.

W. Earl Turner, vice president of Texaco Independent Producers and Royalty Owners, said he was optimistic about potential oil finds in Liberia and mildly interested in onshore exploration in the Ivory Coast.

The Ivory Coast is considered a showcase of economic and agricultural development in Africa. Its 7.3 million people enjoy one of the highest annual per capitia incomes on the continent -- $1,113.

Credit for the country's success since independence in 1960 is largely given to president Felix Houphouet-Boigny, 74, a wealthy Cocoa farmer under colonial rule. He emphasized development of the country's agriculture to produce cash crops for export.

In 1977 the government decided to exploit modest quantities of oil discovered nine miles off the coast. Recoverable reserves are estimated at 11 million barrels, a figure that could increase if water injection proves feasible or if additional fields are discovered.

Currently, Exxon is developing the offshore field and expects to begin production in 1980. Output is expected to peak at about 8,000 barrels a day by 1983 and continue at that level for a year before starting to decrease.

The bankers traveling with Young, including Export-Import Bank Chairman John Moore Jr., said private American investments in the Ivory Coast currently total $250 million.

The banking sources said they hoped that the visit to Nigeria would enhance the investment climate in that oil-rich country.

Moore said the United States had been trying to win over new markets in Nigeria, where U.S. guaranteed investments now total $35 million with an additional commitment for $10 million for a telecommunications project.

"So far, we have not gotten very far. But we did not have the rapport. With Andy Young, things are now shaping up," Moore said.