Legal experts said the activists appeared set for unfair trials and would almost certainly be convicted in a show of determination by the government that any public display of opposition would not be tolerated. If convicted, they could each spend up to five years in prison.

"The expected sentencing of Xu is a message to activists, intellectuals, entrepreneurs and NGOs that there is no place for civil society in Xi Jinping's China unless it walks in lockstep with the party and the government," said Nicholas Bequelin, a senior researcher at Human Rights Watch.

Xu, 40, founded the New Citizen movement in May 2012 to push for social equality and the rule of law, but the drive has been seen by the authorities as a threat to social stability. He was detained in July and formally arrested a month later on the charge of "assembling a crowd to disrupt order in a public place". Prosecutors indicted him last month.

Police accused him of "organising, masterminding and implementing" at least five protests last year to demand that government officials disclose their assets, and at least two others to seek equal education rights for migrant children in Beijing.

Xu's trial is set for tomorrow at the Beijing No1 Intermediate People's Court. The trial of fellow activist Zhao Changqing will take place on Thursday at Beijing's Haidian district court while those of activists Ding Jiaxi , Li Wei , Zhang Baochang and Yuan Dong are slated for Friday at the same court, their lawyers said.

Analysts said that the authorities have over the past year stressed the need to step up control over the internet and escalated crackdowns on freedom of expression by targeting activists and online opinion makers.

The prosecution of the New Citizen activists appears to be part of that drive, they said.

Teng Biao , a legal scholar who has known Xu since his university days, said the authorities have been wary of Xu's campaigns during the past 10 years.

And Xu's New Citizen movement - with its extensive network and ability to mobilise campaigns - combined with his writings on his political ideals "have made them feel he is posing a huge threat", Teng said.

Legal experts and lawyers representing the activists said the arrangement to have defendants of the same case tried separately is unfavourable for their defence and that it breaches court regulations that defendants from a single case should be handled by the same court.

The timing of the trials - just a week before the Lunar New Year - was also seen as designed to lessen their impact as most of the defendants' supporters would be busy travelling for the holidays.

Xu's lawyer Zhang Qingfang said judges at a pre-trial meeting refused Xu's request that witnesses and the co-defendants named in his case be allowed to testify in court. Xu is planning to remain silent in protest.

"There seems no prospect of a fair trial since the facts are seriously in dispute and yet key witnesses will not be allowed to testify in court," said China law expert Jerome Cohen at New York University. "The trial will thus be a farce."

Fellow activists and lawyers said Xu was not the "ringleader" of street protests and in some cases had no knowledge of the events. "He is not very supportive of street campaigns and lots of times he wasn't even informed," said activist Hu Jia .

Eva Pils, a China law expert at the Chinese University of Hong Kong, said “if a legal expert of Xu Zhiyong’s stature announces he will preserve silence at the trial due to the unfairness, and if the defence lawyers in the (activists’) trials view the upcoming trials as pieces of theatre in which they are merely asked to act a part, this tells you that the trials are not seen as a meaningful opportunity to engage in real defence.”

Legal expert Cohen feared the government’s targeting of moderate campaigners such as Xu would deter people from speaking out.

“Eventually such pent-up grievances may lead to the more radical expression of dissatisfaction,” he said.