If convicted, Zhang Shanguang could face the death penalty, according to human rights campaigners.

The labour rights activist is reportedly accused of telling foreign organisations about human rights abuses and farmers' protests.

Mr Jiang was jailed after the Tiananmen Square protests

Mr Zhang, 45, was detained five months ago after he tried to set up a pressure group to help laid-off workers.

The dissident, who has already served seven years for labour rights campaigning, is due to go on trial on Sunday in Huaihua city in Hunan province.

Human Rights in China, a New York-based group, said Mr Zhang was accused of "illegally providing intelligence to overseas enemy organisations and people".

Under China's criminal code, offenders are usually sent to prison, but the court can apply the death penalty if it deems that national interests were seriously endangered.

Mr Zhang's wife, Hou Xuezhu, said her husband in March had told Radio Free Asia - which is funded by the US Government - about taxes charged to Chinese farmers.

She said he had done nothing to break the law and called for his release.

Mr Zhang was originally jailed after a nationwide crackdown that followed the crushing of demonstrations in Beijing's Tiananmen Square in 1989.

Mr Jiang has vowed to get tough

His new trial follows those of Xu Wenli, Qin Yongmin and Wang Youcai, three of China's most prominent dissidents.

They were sentenced this week to 13, 12 and 11 years respectively for trying to establish the China Democracy Party to challenge communist rule.

Their convictions sparked immediate worldwide condemnation with the US calling the sentences deplorable.

But the Chinese authorities warned they would continue to take a tough line and dismissed the criticism as foreign interference.

The crackdown comes just 11 weeks after China signed the United Nations International Covenant on Civil and Political Rights which guarantees freedom of speech.

But President Jiang Zemin warned last week that subversive activities would be "nipped in the bud" and said China would never tolerate Western-style democracy.