A Chinese human rights lawyer charged with state subversion over two years ago will make a court appearance the day after Christmas, his wife said Monday.

Li Wenzu, who last week shaved her head in protest of her husband's indefinite detention, posted on Twitter that Wang Quanzhang would be going to trial in two days in the northern city of Tianjin.

"On December 24, 2018, Christmas Eve, I found out: the trial starts the day after Christmas," Li wrote.

"December 26 is an especially meaningful date. The court session starts at 8:30am (1230 GMT) so Beijing-based me will have to leave bright and early."

Wang, who defended political activists and victims of land seizures, disappeared in the sweep aimed at courtroom critics of Communist authorities.

Charged in January 2016 with alleged "subversion of state power", Wang is the only one of over 200 lawyers and activists arrested in the so-called "709 crackdown" in 2015 who is yet to be tried or released.

In April, Li attempted to march 100 kilometres (60 miles) to a detention facility in neighbouring Tianjin to highlight her husband's plight before she was thwarted by police.

A month later, she met with German chancellor Angela Merkel in Beijing -- a rare opportunity as heads of state often avoid making public statements about human rights during trips to China.

It is not the first time the Chinese government has chosen to sentence a political dissident during the year-end holiday season when international attention towards human rights cases is at a lull.

On Christmas Day 2009, Nobel laureate and Chinese dissident Liu Xiaobo, who died of terminal liver cancer last year while under police custody, was sentenced to 11 years in prison for subversion.

Last year, Chinese activist Wu Gan, who refused to plead guilty to charges of "subverting state power", was sentenced to eight years in prison the day after Christmas.

"We think this is deliberate because obviously a big part of the world will be having a holiday and will not be able to respond", Doriane Lau, China researcher at human rights organisation Amnesty International, told AFP.

"It will also mean that journalists and diplomats... are less likely to try to attend the trial," Lau said, adding that Chinese authorities have used this tactic "many times before".