Junichiro Hironaka, chief lawyer of Carlos Ghosn. Picture: Issei Kato / Reuters.

Tokyo - A prominent Japanese lawyer representing former Nissan chairman Carlos Ghosn said on Monday that he is confident his client can win a court victory.

Junichiro Hironaka, nicknamed "The Razor," who was appointed in mid-February to lead the defense team, told a news conference that he believes Ghosn is innocent of all charges against him.

Ghosn, who led the Renault-Nissan-Mitsubishi Motors alliance, was charged with falsifying financial reports and aggravated breach of trust.

Since Ghosn's arrest in November, Japan's so-called "hostage justice" system, in which criminal suspects are detained for a long period of time to squeeze out a confession, has gained renewed attention and been criticised at home and abroad.

Ghosn, who was sent by Renault to lead a turnaround at Nissan after its near-bankruptcy in 1999, has been in custody at a detention centre for about three and a half months.

Hironaka expressed concerns that the case could scare overseas businesses away from Japan, so it is also "very important for the future of Japanese society," he said.

"I hope that Mr Ghosn can be clearly found innocent soon in order to regain the trust of Mr Ghosn and that of the international community," he said.

Ghosn was indicted over alleged under-reporting of his pay package for years by millions of dollars and transferring of his personal investment losses to Nissan in 2008.

Ghosn denied the allegations.

Hironaka said Nissan was aware of such issues more than 10 years ago and did not question them then.

He found it "bizarre" that the carmaker instead took them to the prosecutors now.

Hironaka said he has met Ghosn at the Tokyo Detention Centre several times and found him in good health despite his prolonged detention.

The lawyer added that he read some of Ghosn's books in order to understand his ways of thinking.

Hironaka has won some high profile cases, including the 2012 acquittal of influential lawmaker Ichiro Ozawa, who was charged with alleged false reporting by his political funds body.

On Thursday, his team filed its first request with the Tokyo District Court on behalf of Ghosn to end his detention.

The previous defense team made requests twice in January, which were rejected.

"I'm more optimistic" as to whether his client can be released on bail, Hironaka said.

"We have presented our own convincing application, showing that there is indeed no flight risk or no risk of tampering evidence," said the lawyer.

"I'm now 73 years old. However, I want to test how sharp my razor still is," he said.

dpa