China on Monday jailed the leader of an unofficial Protestant church for nine years for "incitement to subvert state power".

Pastor Wang Yi, whose Early Rain Covenant Church was the target of a government crackdown last year, was also found guilty of "illegal business operation" by a court in southwest China's Chengdu, according to an announcement on an official court website.

Wang was detained in December 2018 in a raid by authorities in which dozens of members of his "underground church" disappeared.

Protestants in the country are split between unofficial "house" or "underground" churches like the Early Rain Covenant Church, and state-sanctioned churches where Communist Party songs also feature in the order of service.

Catholics are similarly divided between unofficial churches led by bishops recognised by the Vatican and those who follow official prelates.

China's officially atheist government is wary of any organised movements outside its own control, including religious ones.

Chengdu's official court system website said Wang had been convicted in an open trial by a court in the city, where Early Rain Covenant Church had been based.

The charge of inciting subversion has often been used against dissidents as a way to silence criticism of the government and the Communist Party.

Shortly before being detained, Wang wrote a post on his church's Facebook page criticising the Chinese government for repressing Christians in the country, saying the "Party can flourish for a while, but it cannot last forever."

"The Party can kill my body, but it cannot kill my soul," Wang wrote.

Patrick Poon, a Hong Kong-based researcher with Amnesty International, said Wang's sentence would "have a chilling effect on other house churches in China".

"The message is very clear — you will be the next Wang Yi if you don't register and follow the Communist Party's line on religion,” Poon told AFP.

Wang's church was among a number of prominent "underground" churches shut down by the Chinese government in 2018 as part of a crackdown on religion, especially on followers of Islam and Christianity.

Beijing-based Zion Church, one of China's largest "underground" Protestant churches, was banned by city authorities in September 2018 for operating without a licence after dozens of officials stormed its premises.

Earlier that year, unauthorised versions of the Bible were pulled from Chinese online retailers.

China has faced international condemnation for rounding up an estimated one million Uighurs and other mostly Muslim ethnic minorities in internment camps in the northwestern region of Xinjiang.