An activist in central China was sentenced to hard labour after opposing the government's handling of the alleged suicide of 1989 Tiananmen democracy protest leader Li Wangyang, a lawyer said Monday.

Xiao Yong was sentenced without trial to 18 months reform-through-labour on Friday in Shaoyang city after he opposed a government report released earlier this month that Li committed suicide, rights lawyer Pang Kun told AFP.

Li, 62, spent 22 years in jail for his role in the Tiananmen protests and was found dead under suspicious circumstances on June 6 in a Shaoyang hospital, in central China's Hunan province.

His death sparked an outpouring of protests in Hong Kong and by mainland rights activists, who refused to believe Li committed suicide and alleged that he could have been tortured by security guards at the hospital.

"I can't say for sure that Xiao Yong was sentenced because of the Li Wangyang incident," lawyer Pang told AFP, "but it appears that this is the case."

The activist, a friend of Li, had spent a month in detention earlier this year for protest activities and had been repeatedly warned by police not to get involved with the Li case before being taken in, Pang said.

In China, "reform-through-labour" is an administrative punishment meted out by police and does not require a trial.

Pang said police detained Xiao after arriving at the activist's residence with notice of the punishment, ostensibly for a years-old, previously dismissed charge over a stolen motorbike.

Police in Shaoyang hung up their phones when contacted by AFP on Monday.

Xiao's family was hoping to hire Pang to bring a case against the police over apparent illegalities in the sentencing, the lawyer said, but police broke up a meeting at the family home on Saturday and briefly took him into custody.

"The family wants to hire me, but they are getting too much pressure from the authorities, so we will have to wait to see if a lawsuit can be brought later," Pang said.

According to New York-based Human Rights in China (HRIC), Li, nearly blind and with crippled legs, was found on June 6 strung up to a windowsill by a bandage wrapped around his neck, with both his feet on the ground.

He had been under round-the-clock police surveillance at the time, the group said.

Li's sister and brother-in-law and several supporters in Shaoyang disappeared following the death and are believed to be in police custody. Their mobile phones were turned off Monday as they have been for weeks.

The activist served 11 years in prison for "counter-revolutionary" crimes following the Tiananmen protests and then a further 10 years after a 2001 conviction for "inciting subversion".