Masako Mori told reporters at a news conference the ministry has already acted to prevent a recurrence but declined to give details. Speaking a week after Ghosn showed up in Lebanon, due to the New Year holidays in Japan, she defended the judicial system that he fled, insisting he would not get a fair hearing.
She was asked about reports that Ghosn had hidden in a box and that baggage checks at a regional airport might have been insufficient.
Ghosn, who was chairman of Nissan-Renault-Mitsubishi at the time of his arrest, skipped bail while awaiting trial on various financial misconduct allegations and later said from Lebanon that he did it to escape injustice.
Mori declined to say who might be held responsible for such a high-profile flight, stressing it was still under investigation.
She said Ghosn left illegally, denouncing it as an "unjustifiable" crime.
"Japan's justice system allows investigating the facts while it ensures the individual basic human rights at the same time," Mori told reporters at the ministry.
"It is set with appropriate procedures and it is operated appropriately."
But she acknowledged the case was being looked at under an ongoing review of the nation's judicial system, including introducing electronic tethers to monitor those out on bail.
"We are aware of the criticisms," Mori said, referring to human rights advocates' descriptions of Japan's legal system as "hostage justice."
Ghosn and others say Japan's system is too slow and is inhumane. Ghosn was banned from meeting with his wife while out on bail. Preparing for his trial has taken more than a year, and a date has not been set. Ghosn was detained, twice, for a total of 130 days before he was released on bail a second time.
Mori said each nation has its own judicial system and arrests are rarer in Japan than in other countries, suggesting arrests are made only when the authorities are fairly confident they have a case.
"Simple comparisons are misleading," she said.
French Finance Minister Bruno Le Maire said Monday that he was surprised by Ghosn's escape, He wants a broader investigation into suspected financial wrongdoing by Ghosn at the alliance between Renault SA, which is partly owned by the French government, Nissan and Mitsubishi Motors.
"When you are an individual subject to laws, you don't escape justice. And Carlos Ghosn is an individual like any other," Le Maire said Monday on France-Inter radio. "He should answer before the justice system."
Le Maire wouldn't say where Ghosn should be prosecuted., but said that as Renault's biggest single shareholder, the French government wants to ensure the struggling automaker prospers again.
French investigators are investigating Renault. Le Maire reiterated calls for a broader probe into 11 million euros ($12.3 million) in questionable expenses at the alliance's Netherlands-based headquarters under Ghosn's watch.
Takashi Takano, one of Ghosn's lawyers in Japan, said he felt sad and betrayed Ghosn didn't try to win a verdict of innocence in court. He also said he understood how Ghosn might have lost hope not only with the prosecutors but with the entire Japanese judicial system. Ghosn's legal team said they did not know about his escape plan.
Yuichi Kaido, another lawyer, said he was troubled by public support for denying bail to all foreign suspects. He said in an online statement he feared Japan might react to international criticism of its legal system by becoming more insular and rigid in its views.
Details of Ghosn's stunning escape are unclear. But Turkish airline company MNG Jet said two of its planes were used illegally, first to fly him from Osaka, Japan, to Istanbul, and then on to Beirut, where he arrived on Jan. 30. He has not been seen since, but has promised to speak to reporters on Wednesday.
Lebanon has said he entered legally with a French passport.
Once an auto industry superstar, Ghosn was first arrested in November 2018. While out on bail, he was living in a home in an upscale part of Tokyo under strict surveillance as part of the conditions for his release. That raises questions about how he left undetected.
Security cameras at his home operated 24 hours a day, but the footage only had to be submitted to the court on a monthly basis, according to lawyers' documents detailing Ghosn's bail conditions.
Ghosn is charged with under-reporting his future compensation and breach of trust in diverting Nissan money for his personal gain. He insists he is innocent.
His bail has been revoked, and Interpol has issued a wanted notice. Japan does not have an extradition treaty with Lebanon, but Mori left open the possibility Japan could seek Ghosn's return.
But such a return so far appears unlikely, and Japan's options are limited.
Mori stressed that any retaliatory action, such as economic sanctions, must be decided on very carefully. She would not say if Japan has contacted the U.S. or France for help.
"It is indeed possible to ask for extradition of criminals based on the principle of reciprocity," she said, replying to a question about Lebanon.
"But, upon doing that, we need to carefully study whether it is possible to guarantee this principle of reciprocity and their internal justice system."