Two Chinese activists who were tried after holding small anti-corruption protests were found guilty Wednesday and one was sentenced to 18 months' jail, a court said.

Yuan Dong and Hou Xin belonged to the New Citizens rights movement, which campaigned against official graft among other issues and has faced a crackdown over the past year.

China's new leaders under President Xi Jinping have also prioritised tackling corruption. But they fear any organised movement that might challenge the control of the ruling Communist Party.

Both activists were found "guilty of gathering a crowd to disrupt public order", the Haidian district court in Beijing said on a verified social media account.

Yuan was given 18 months in prison but Hou "was spared criminal punishment given the relatively light criminal context", it added.

So far 10 members of the New Citizens network have gone on trial on charges of disrupting public order, and at least 20 have been detained, members say.

Many of them held banners in public urging officials to disclose their assets as a check against corruption, and posted photos of their protests online.

The movement's founder, prominent legal activist Xu Zhiyong, was on Sunday the first to be convicted and was given a four-year sentence. His lawyer said he plans to appeal.

Xu's sentence elicited international criticism, with human rights group Amnesty International calling it "shameful" and the United States saying it was "deeply disappointed".

A small group of Taiwanese rights activists rallied outside the presidential office in Taipei on Wednesday in support of Xu.

The New Citizens Movement, believed to number just hundreds nationwide, has championed causes ranging from official graft to education equality.