A Chinese court has jailed two activists for taking part in small-scale pro-democracy protests after detaining them for nearly three years, their lawyer said Tuesday.

Yuan Bing and Yuan Xiaohua were jailed for four years and three-and-a-half years respectively, on charges including "picking quarrels and making trouble", their attorney Lu Jingmei told AFP.

A court in the central Chinese province of Hubei convicted them over a series of protests around the country in which they held signs in public places calling for freedom and democracy, Lu added.

Their tour, dubbed "Enlightening China", saw them demonstrate, make speeches and meet activists in nine cities, according to China Human Rights Defenders, an overseas-based advocacy group.

The two men, who are not related, were held in detention for 34 months before being put on trial, Lu said.

China's President Xi Jinping has overseen a crackdown on dissent since coming to power in 2012, with hundreds of lawyers, activists and academics detained and dozens jailed.

The charge of "picking quarrels" has increasingly been used by courts to jail activists over small-scale street protests.

Beijing often says human rights have improved in China in recent decades, citing economic growth as an example.