Sudan's military government, which overthrew the pro-American regime of Jaafar Nimeri last April, intends to hold elections to establish a new multiparty democracy within the next five months, according to a high-ranking Sudanese delegation visiting here.

Civilian Prime Minister Gizzuli Daffa-Allah, who heads the group, said one of his primary missions is conveying to the Reagan administration that last April's events were a "bloodless popular uprising" that will lead to real democracy after 16 years of one-man military rule.

"We want to make it clear to everybody that the Sudanese have opted for democracy and for multiparty democracy, all of us, civilians and military," he said in an interview with Washington Post editors and writers as he began a three-day visit.

Elections, he said, would take place before next April although no progress has been made toward ending the civil war in southern Sudan and despite continuing signs of military discontent that led to an abortive military uprising in Khartoum last month.

Daffa-Allah also indicated that he is seeking financial and political support of the administration and such Washington-based financial institutions as the International Monetary Fund and the World Bank to help Sudan through what he called "a difficult transitional period" to civilian rule.

"This is the time for people who are concerned with democracy, freedom and real progress to put their efforts behind the Sudan so that we make sure that what's coming after the transitional period is a continuation of democracy and nothing else," he said.

Sudan's debt and financial crisis have been important contributors to rethinking inside the administration about how to deal with the African debt issue, particularly failure of an increasing number of nations to repay IMF standby loans.

Sudan's almost $200 million debt represents about half of all money owed the IMF, an administration official said.

Default on repayments of IMF loans has made it impossible for Sudan to renegotiate with western creditors rescheduling its overall debt, now more than $8 billion.

Radical economic reforms led to street rioting last April that provoked Nimeri's overthrow by a combination of military and civilian elements, the latter led by Daffa-Allah.

The prime minister gave no indication that any breakthrough has been made in resolving Sudan's economic problems. "We need cash, and naturally cash is in very short supply," he said.

Daffa-Allah said the effects of famine, which has threatened the lives of 5 million Sudanese in the last year, continue to burden the economy despite prospects for a very good harvest and a new government emphasis on "supply side" economics to boost growth.

"It is very difficult for the people to be asked for more sacrifices," he said. "This human element, this political element, must be taken into consideration."

Daffa-Allah said "all concerned governments and financial organizations" must have "the courage and the imagination" to look into new policies in dealing with Africa's economic problems.

He said John Garang, leader of the southern insurgency, recently sent him a letter saying he was "for dialogue, a unified Sudan and democracy" but also demanding dissolution of the government and ruling provisional military council as a precondition for talks.

Daffa-Allah said this constitutes "a rather impossible situation."