Niger President Seyni Kountche brought the African drought and hunger crisis to the White House yesterday during a meeting in which President Reagan pledged that the United States would use "significant means" to alleviate widespread famine in the continent.

Kountche, president of an arid nation of 6 million, said he and other African leaders are "preoccupied by the harsh drought that is once again affecting extensive areas of our continent" and has caused a "reappearance of hunger in many countries."

Niger, where the drought reduced this year's harvest by about 60 percent, is one of the five hardest-hit countries in Africa. State Department officials said the drought has forced about one in 12 persons to migrate in search of food.

Reagan met with Kountche, who is spending two days in Washington, in the Oval Office and gave a lunch in his honor.

The United States later signed an agreement to donate an additional 45,000 metric tons of emergency food to Niger, whose problems have largely been overlooked as attention has focused in recent months on the dramatic famine situation in Ethiopia.

The relief supplies will cost about $17 million and will begin arriving in the West African nation in February.

Kountche, who is making his first official visit to Washington, said in an interview after his meeting with Reagan that the food agreement demonstrated that "for the United States, food aid is not a matter of ideology but of humanitarian concern. Now it is up to those of us in Africa to overcome the failures in agriculture and in development that we have contributed to, and to work with the West in developing a new strategy of development."

After getting through 1984 with the help of food aid, "we will have to make 1985 the decisive year through our own efforts if we are going to be able to stabilize our own food production programs," he said.

Kountche's remarks and his presence in Washington this week, while the leaders of other former French colonies were gathering in Burundi for their annual summit meeting with French officials, underscored the advances that aid to famine-stricken areas and strong opposition to Libya's Col. Muammar Qaddafi are bringing for the United States in West Africa.

During departure ceremonies, Reagan praised Kountche as an "example of leadership that Africa will need to solve its problems."

"There was a good understanding on what was discussed," Kountche said. "I'm glad to note President Reagan and his administration are fully aware of the situation and seriously concerned about the great suffering" in Africa.

Kountche, the first African head of state to meet with the American president since last month's election, said that Reagan, "essentially in a humanitarian spirit," assured Kountche that the "United States will continue to decisively help in the crusade against hunger and death in Africa."

The 45,000 metric tons of sorghum will be donated under the Food for Peace program. The aid is in addition to 15,000 tons that the administration agreed to donate in October.

Officials estimated that Niger's harvest fell about 350,000 tons short of providing enough food to feed its population this year, and they broadly hinted that further aid will be forthcoming.

The food situation in Niger was complicated last year when the nation was forced to sell off about 50,000 metric tons of surplus stockpiles it had built up to repay debts to French banks, U.S. officials said.

In his farewell remarks, Kountche said he and Reagan had had very extensive discussions on the "effects of world recession, the persistent drought, famine and flashpoints on all continents."

Among the specific items brought up by the Niger president was South Africa, where he said apartheid represents "an intolerable, untenable situation." The two leaders also discussed the potential threat to Niger by Libya, which borders it.

"We support Niger's efforts to maintain its independence and territorial integrity," Reagan said after the meeting.

A senior U.S. official, who attended the meetings, said Kountche stressed a need to "reorient development efforts" in the Third World. He said the Niger president believes that most African nations have "made their share of mistakes" since gaining independence and "these mistakes have been encouraged by donor institutions."

Niger, formerly part of French West Africa, gained its independence in 1960. It has been ruled since 1974 by a military government that permits elections only for local development councils. It is a poor nation without a railroad.