TAIPEI (Reuters) - The wife of Taiwan activist Li Ming-che, sentenced to five years in prison by Chinese authorities for subverting state power, was stopped from flying from Taiwan to China on Tuesday to visit him in prison, rights groups said.

FILE PHOTO - Li Ching-yu (C), wife of Taiwanese human rights activist Li Ming-che, detained in China, attends a news conference in Taipei, Taiwan March 31, 2017.REUTERS/Tyrone Siu

Li Ming-che, a community college lecturer and an activist at a human rights non-governmental organization in Taiwan, had gone missing while on a trip to China in March. Chinese authorities later charged him with subverting state power.

His wife, Li Ching-yu, refused to recognize the court’s authority during the first hearing.

She bought a plane ticket on Xiamen Airlines on Tuesday, with plans to see her husband in prison, according to a statement by several human rights group who are assisting her.

However, because she had travel documents that were deemed invalid to enter China, she was not permitted to board the plane in Taipei, the statement said.

Taiwanese need special travel documents issued by China, akin to a passport, to travel to China. The documents can be invalidated unilaterally by the Chinese government.

The rights groups’ statement said Li had received a notice from the Chinese government on Monday notifying her that her husband was transferred to a Hunan province prison on Dec. 28. It said family members were entitled to visit once a month.

Asked about the incident, China’s Taiwan Affairs Office spokesman Ma Xiaoguang told a regular briefing on Wednesday Hunan had not received detailed information required for a visit from Li Ming-che’s family.

“As per the rules, the jail will handle applications for a visit in accordance with law after they are processed,” Ma said without elaborating.

Li was also denied entry into China in April despite having valid credentials, the associations said. She was told at the time by the airlines that her travel credentials were canceled.

“From past years until now, the Chinese government’s refusal today to let family members visit relatives in prison in China demonstrates that they do not empathise to any degree, from the point of view of humanity,” the rights associations said.

The Straits Exchange Foundation, a semi-official body that oversees relations between Taiwan and China, echoed the statement, calling on Chinese authorities to approve credentials for Li to travel to China and arrange for a prison visit.

Li could not be reached for comment on Tuesday.