The former chairman of Nissan Motor Co., Carlos Ghosn, appears to have left the Tokyo Detention Centre after posting 1 billion yen ($8.9 million) bail.

Ghosn left the facility in disguise, wearing a surgical mask, glasses, a hat and a construction worker's outfit. Ringed by security guards, he was driven away in a silver van and did not speak to the gaggle of reporters standing watch.

The man's identity could not immediately be confirmed with authorities, but the resemblance was clear.

Japanese TV networks followed the van's journey from the detention center on the eastern outskirts of Tokyo toward downtown. Ten motorcycles trailed the van as it passed largely unnoticed through city streets.

Ghosn, the former head of the Renault-Nissan-Mitsubishi Motors alliance, was arrested on November 19. He is charged with falsifying financial reports and with breach of trust.

The Tokyo District Court confirmed the 1 billion yen ($8.9 million) bail was posted earlier in the day, after a judge rejected an appeal from prosecutors requesting his continued detention. That cleared the way for Ghosn to leave the facility after spending nearly four months since his arrest on November 19.

Ghosn's wife Carole Ghosn and one of his daughters were seen leaving the detention centre earlier in the day.

Before his release, Ghosn, who turns 65 on Saturday, issued a statement reasserting his innocence.

'I am innocent and totally committed to vigorously defending myself in a fair trial against these meritless and unsubstantiated accusations,' he said.

A date for his trial has not yet been set.

One of Ghosn's lawyers, Junichiro Hironaka, said his legal team had offered new conditions for his release, such as a surveillance camera at his doorway and a promise not to use the Internet. He is allowed to make voice calls, but he cannot travel abroad.

Suspects in Japan often are detained for months, especially those who insist on their innocence, like Ghosn. Some legal experts, including Hironaka, have criticised the system as 'hostage justice,' saying the long detentions tend to encourage false confessions.

Prosecutors contend that suspects may tamper with evidence and shouldn't be released. Two of Ghosn's earlier requests to be released on bail were rejected.

Some critics of Japan's legal system hope that Ghosn's release, so many weeks before preparations for his trial are ready, may set a precedent, helping bring about change.

Ghosn says he did not falsify financial reports because the compensation he is alleged to have under-reported was never paid or decided upon. The breach of trust allegations center on a temporary transfer of Ghosn's investment losses to Nissan's books that he says caused no losses to the automaker. The charge also points to payments to a Saudi businessman that he says were for legitimate services.

Nissan declined comment on the criminal case against Ghosn but said an internal investigation had found unethical conduct. Nissan has dismissed Ghosn as chairman, although he remains on the board pending a decision at a shareholders' meeting.

Ghosn's family has said that he has lost weight while in detention, and he looked thinner in his court appearance. Hironaka has said he is in good spirits. Ghosn thanked his family and friends, who, he said, 'stood by me throughout this terrible ordeal'.