The jailing came the same day a closed junta court sentenced ousted leader Aung San Suu Kyi to another six years in prison for corruption, according to a source with knowledge of the case, taking the Nobel laureate's total jail time to 26 years.

Toru Kubota, 26, who was detained in July and jailed for seven years last week, was sentenced to an additional "three years imprisonment", a diplomatic source at Japan's embassy said, citing the journalist's lawyer.

Myanmar's junta has clamped down on press freedoms, arresting reporters and photographers, as well as revoking broadcasting licences during its crackdown o dissent since seizing power last year.

Kubota, who was detained near an anti-government rally in commercial hub Yangon along with two Myanmar citizens, appeared in good health at the hearing on Wednesday, the source said, citing his lawyer.

According to a profile on FilmFreeway, Kubota has previously made documentaries on Myanmar's Muslim Rohingya minority and "refugees and ethnic issues in Myanmar".

Kubota is the fifth foreign journalist to be detained in Myanmar, after US citizens Nathan Maung and Danny Fenster, Robert Bociaga of Poland and Yuki Kitazumi of Japan -- all of whom were later freed and deported.

Before the verdict was announced, junta spokesman Zaw Min Tun told AFP that Kubota "would not be deported at this moment," without giving details.

- 'Sham trial' -

Suu Kyi, 77, has been detained since the generals toppled her government in a coup on February 1 of last year, ending the Southeast Asian country's brief period of democracy.

She has since been convicted on a clutch of charges, including violating the official secrets act, electoral fraud and illegally possessing walkie-talkies.

In the latest case, Suu Kyi was "sentenced to three years imprisonment each for two corruption cases" in which she had been accused of taking bribes from a businessman, the source said.

The terms will be served concurrently, the source added.

The businessman, Maung Weik, appeared in a video televised by a military broadcaster last year claiming he had given Suu Kyi $550,000 over several years.

Maung Weik -- who was convicted of drug trafficking in 2008 -- also said he had donated money to senior figures in Suu Kyi's government for the good of his business.

Suu Kyi -- who denies all charges against her -- appeared in good health and will appeal, the source added.

She is currently on trial for five other corruption charges. Each carries a maximum 15 years in prison.

A spokesperson for Amnesty International on Wednesday slammed the trial as a sham that "cannot be taken seriously".

A junta spokesman did not respond to a request for comment.

Journalists have been barred from attending the court hearings and Suu Kyi's lawyers have been banned from speaking to the media.

In June, she was transferred from house arrest to a prison in the capital Naypyidaw, where her trials are being held in a courthouse inside the prison compound.

Myanmar has been in turmoil since the military seized power, sparking widespread armed resistance.

The junta has responded with a crackdown that rights groups say includes razing villages, mass extrajudicial killings and airstrikes on civilians.

More than one million people have been displaced since the coup, according to the United Nations children's agency.

According to a local monitoring group, more than 2,300 people have been killed and over 15,000 arrested since the military seized power.