An independent auditor probing Mexico's scandal-plagued banking system delivered his final report to Congress today, firing the starting gun for what promises to be a highly political debate as the country heads into a presidential election campaign.

The 240-page report by Michael W. Mackey, a Canadian hired by the Chamber of Deputies a year ago, described the near collapse of Mexico's banking system in the mid-1990s and its rescue with billions of dollars in government funds. It confirmed that the system suffered from numerous problems, including corruption, weak regulation and poor oversight.

Perhaps most fundamentally, according to the report, the privatization of banks in 1991-92 was flawed, leaving many financial institutions poorly capitalized and in the hands of owners with little banking experience who approved large, inadequately secured loans to themselves, their friends and families. The report found about $640 million in potentially illegal loans that were not repaid.

But it did not uncover serious wrongdoing by government officials in their handling of a controversial bank rescue program, now expected to cost Mexico more than $82 billion, up from estimates of $60 billion a year ago. Opposition parties had hoped to find proof that high-ranking members of the ruling Institutional Revolutionary Party, known as PRI, or the administration of President Ernesto Zedillo had acted illegally or somehow profited from the banking fiasco.

"It has been proven that the PRI acted responsibly," said PRI congressman Jorge Estefan. "The government comes out very clean."

But opposition legislator Dolores Padierna of the center-left Democratic Revolutionary Party said the PRI blocked the release of names of people who defaulted on loans or acted illegally and refused Mackey access to bank records detailing allegedly illegal contributions to the ruling party. "This seems scandalous to us," she declared.

As parts of the report leaked out over the past few weeks, administration and PRI officials have accused the opposition of being on a witch hunt. But with one of the most competitive presidential elections ever less than a year away, it seemed unlikely that the opposition will back away from political corruption allegations even if they are not endorsed by the report.

Opposition leaders have accused the government of not turning over bank records showing that a disgraced financier and former bank owner, Carlos Cabal Peniche, funneled $25 million to PRI campaigns in 1993 and 1994, including Zedillo's presidential effort and the gubernatorial campaign of Roberto Madrazo, who hopes to be the PRI's 2000 presidential candidate.

Cabal Peniche has been jailed in Australia and is fighting extradition to Mexico, where he is wanted on fraud charges. PRI officials have acknowledged his contributions but said they were legal. They said banking secrecy laws prohibited them from giving Mackey certain records from Cabal Peniche's banks. Mackey said he was denied access to the records because they were part of another criminal probe.