Nicaraguan President Violeta Chamorro is leaving Washington with assurance from President Bush that he will see that her country's $365 million in overdue debt payments is wiped out.

Bush pledged the United States will contribute $50 million toward what Mrs. Chamorro said is her most pressing problem - clearing the arrearage in payments to the World Bank and the International Development Bank on a foreign debt totaling $9.5 billion, said Assistant Secretary of State Bernard Aronson.The president also agreed at the Oval Office meeting Wednesday to press U.S. allies - particularly Japan - to contribute to that effort and made clear to Mrs. Chamorro that the United States will give more financial help toward the debt repayment if needed, officials said.

Administration officials said Mrs. Chamorro's trip to Washington, the first state visit by a Nicaraguan president in 52 years, was significant in demonstrating the new relationship between the two countries.

Taking office a year ago after democratic elections, Mrs. Chamorro replaces the leftist Sandinista government that was despised by the Bush administration and Reagan administration before it.

The Nicaraguan economy is on shaky ground as Mrs. Chamorro tries to undo the Sandinista's Marxist system. The arrearage in debt repayment has made it difficult for Managua to get capital to pay for the national recovery efforts.

The $50 million commitment from the United States is part of the $541 million the United States has earmarked for the Central American nation since Mrs. Chamorro's inauguration, Aronson said.

"The president pledged strong and firm United States assistance to Nicaragua and made it clear that the United states, along with the World Bank, will lead an international effort . . . to help," Aronson told reporters.

Mrs. Chamorro said U.S. aid "was a decisive factor during my first year in office. And now, Nicaragua has begun to recover from the years of political instability and continuous conflict."