"Htin Lin Oo criticized Buddhist monks who had given hate speeches," lawyer Thein Than Oo told Reuters.

The transition by Myanmar, once known as Burma, to democracy four years ago has seen the emergence of a kind of Buddhist nationalism rarely seen under the military's five decades of strict rule.

Long simmering tension between the Buddhist majority and its minority Muslims has surfaced with the lifting of bans on protests and easing of censorship and has at times spiraled into rioting and deadly religious violence. Muslims have been worst hit. The lawyer said he feared his client's previous involvement with the opposition party had raised the profile of the case, of which the decision would be appealed.

Thein Than Oo said a 10-minute video segment of his client's two-hour speech that circulated online in October last year was purposefully misinterpreted by extremists.

The verdict was condemned by rights groups for sending the wrong message.

Myanmar's government "should be encouraging writers like Htin Lin Oo to promote interfaith tolerance in the country, rather than sending him to jail," Wai Hnin of the Burma Campaign UK said in a statement.

London-based Amnesty International said Htin Lin Oo was a prisoner of conscience who should be freed immediately.

"The growing influence of extremist Buddhist nationalists and their hateful rhetoric in Myanmar is deeply troubling," Amnesty's regional research director Rupert Abbot said in a statement.

"The government seems intent on compounding the problem by imprisoning those speaking out against religious intolerance."