Former president Jose Lopez Portillo, directly defending himself before the Mexican public for the first time, declared today that reports linking him to pervasive corruption under his administration are "lies and calumny."

Lopez Portillo, who was replaced by President Miguel de la Madrid in December 1982, spoke out after President Jose Azcona of Honduras was quoted in a newspaper interview here as saying the former Mexican leader "took off with money" and "banked $100 million or $1 billion" during his six-year tenure.

"Mr. Azcona, you are defaming me by daring to repeat lightly (and this is the softest way to characterize what you said) lies and calumny," Lopez Portillo said in a letter published on the front page of Mexico City's Excelsior newspaper, which also published the Azcona interview.

"Either you are poorly informed or you are lying. In both cases, you are defaming me," the letter closed. "And this is not worthy of an upright man, much less a president."

Azcona was interviewed by Excelsior as part of a series of articles on Central American leaders, and his comments about Lopez Portillo reflected only a small part of a broad range of issues that he touched on, including the presence of anti-Sandinista Nicaraguan rebels in country.

Lopez Portillo previously had kept a low profile since leaving office, spending much of his time in Europe, aloof from the charges of corruption leveled against his administration. Jose Diaz Redondo, spokesman of the ruling Institutional Revolutionary Party, said today's letter marked the former president's first public attempt to refute such accusations.

Lopez Portillo's silence until now was in keeping with Mexican political tradition, which decrees discretion from former presidents. It seemed particularly appropriate in view of corruption charges brought by the new government against some of Lopez Portillo's closest associates and political allies.

The Mexico City police chief under Lopez Portillo, Arturo Durazo, was extradited from the United States last month on charges of extortion and illegally stockpiling weapons. He has been jailed here pending a trial. The Mexico Federal District prosecutor, Renato Sales Gasque, announced last week that de la Madrid's government also has begun an investigation into Durazo's possible links to other crimes.

Durazo, a childhood friend and longtime associate of Lopez Portillo, became famous in Mexico for his displays of wealth and power during the former administration. While in office, he built a palatial residence outside the capital, boasting stables, a dog track and a vintage automobile collection.

After Lopez Portillo left office, Durazo fled Mexico. U.S. authorities arrested him in San Juan, Puerto Rico, in October 1984 on a Mexican warrant and, after a court battle, handed him over to Mexican authorities last month.

De la Madrid's government, which came to office on a promise to fight official corruption and promote "moral renovation" in Mexican public life, opened the Durazo mansion for a while as a "museum of corruption." Thousands of ordinary Mexicans filed through and got a taste of the luxurious lifestyle they had heard about in rumors.

Another close friend of Lopez Portillo, Jorge Diaz Serrano, has been jailed on charges of involvement in a $34 million fraud as head of Mexico's national oil company, Pemex. At least three other government officials have been charged with fraud during Lopez Portillo's administration.

Lopez Portillo has been charged with no crimes himself and travels in and out of Mexico regularly. But his close association with those charged and the swift accumulation of wealth by Lopez Portillo and officials in his government have generated widespread reports among Mexicans and diplomats here that the former president profited from the conduct of his subordinates, as charged by Azcona.

Since de la Madrid took office, these reports have been widely discussed in the Mexican press and political circles, particularly in light of the government's emphasis on battling the longstanding problem of corruption.

Lopez Portillo, in the letter, suggested these reports were started by political enemies and "agents of slander and destabilization."