MEXICO CITY (AP) _ Mexico hopes to reduce payments on its foreign debt by 50 percent in negotiations next year, the government newspaper El Nacional on Sunday quoted private debt specialists as saying.

In its lead front-page story, the newspaper quoted the sources as saying a 30 percent cut was feasible within a ''realistic term.'' The sources were not identified.

They predicted that an agreement on reducing debt payments as of 1990 would be reached in the first two months of next year, the newspaper said.

Mexico's payments this year on its $102 billion foreign debt are expected to total $14 billion.

Last week, Treasury Secretary Pedro Aspe said the country would seek a reduction in debt service from the current level, the equivalent of 5 percent of gross domestic product, to 3 percent of GDP.