HANOI: A Vietnamese communist official turned democracy activist was put trial on Wednesday charged with anti-government propaganda, in a case activists see as part of a wider crackdown on free speech.

Vi Duc Hoi, 54, published online commentaries on issues including land disputes between citizens and the authorities, his lawyer Tran Lam said ahead of the hearing.

Hoi, who faces a maximum 20 year prison sentence if convicted, is charged with "propaganda against the state", which rights activists say criminalises free speech in the one-party state.

A clerk at the People's Court in northern Lang Son province confirmed that the case was being heard, adding that the trial would likely last one day.

Trials in Vietnam are usually closed to the general public and AFP was not granted permission to attend.

Hoi worked as a district official, including as head of a local state propaganda department, and was a Communist Party member for three decades until he resigned to become a democracy activist, his wife said after his arrest in October.

In 2009 Hoi received an award from US-based Human Rights Watch, which said he wrote articles that criticised and called for democratic reforms. This led to his being placed under house arrest, HRW said.

The United States ambassador has also said the Internet and free expression were increasingly stifled last year during a clampdown that saw almost 40 people arrested or convicted.