A Tunisian military court Tuesday denied bail for a blogger who is appealing his three-year jail sentence for defaming the army -- a case that has alarmed rights campaigners.

The court scheduled the next hearing for Yassine Ayari on January 20.

Ayari, 33, was convicted in November in absentia for having "defamed army officers and senior defence ministry officials," whom he accused of financial abuse.

He was arrested on December 25 on his return from Paris.

New York-based Human Rights Watch has described his conviction as "not worthy of the new Tunisia."

In recent months, Ayari had published blogs critical of the Nidaa Tounes party, which won Tunisia's first-post revolution parliamentary elections in October.

His lawyer Sami Ben Amor described the charges as "political".

"It is in the interest of Tunisia's new rulers to send a positive message to the people," he said.

Dozens of supporters held a protest outside the court demanding Ayari's release, shouting: "No to military trials. Tunisia is a civil state".

"The corruption cases which Yassine spoke out about should be reviewed and he should not be jailed. He did not defame the military. He spoke of the corruption of people within it," the blogger's mother, Saida, told AFP.