Image copyright EPA Image caption Richard Ho, who leads the Beijing-backed Democratic Progressive Party, said the abuse of legal rights and freedoms was unacceptable
A growing crackdown on Hong Kong has prompted fears it could have “chilling” implications for democracy on the self-ruled island of Taiwan.
The government is searching for an ethnic Chinese blogger critical of China.
Hong Kong’s chief magistrate said Chinese authorities had dragged him to court in Shenzhen “on a plethora of fabricated charges”.
China has also set limits on Hong Kong’s freedoms, with the detention of several social media activists and the imprisonment of journalists.
Taiwan, which split from China on the island in 1949, has recently experienced political turbulence, including a rally that left two people dead.
Mr Ho said critics were facing “an increasing number of violations of people’s constitutional and human rights, in general. Many people are being detained,” he told reporters in Taipei.
Taiwan’s opposition Democratic Progressive Party (DPP) has been at the forefront of demands for the island to fully be an independent state from the mainland.
“The mainland government is taking a series of measures to restrain the activities of democrats, and to limit our democratic rights. We’ll keep making efforts to stand up,” Ms Ho said.
Mainland leaders have repeatedly urged the DPP to renounce political independence from the mainland.
In his comments, Mr Ho also said that while Hong Kong was able to obtain “reasonable” freedom of speech, there was also need for “good education” in Taiwan.
According to the Chinese-language Washington Post, Mr Ho was speaking at a conference in Taipei on Thursday in which he expressed concerns over the “spread of reactionary reactionary movements” across China.
BBC China analyst Joshua Newman said the release of nine of 11 sentenced to prison after the sentencing of the independence activist Joshua Wong for damaging government property at a political rally in 2017 was linked to the news.
Wong’s imprisonment was roundly condemned worldwide, and many thought it would lead to the jailing of other activists.
However, prosecutors agreed to release the activists on condition they gave up their political activism and would not engage in criminal activity again.
Dozens of activists have been jailed in recent years, charging on terrorism, separatism and subversion of state power.
Image copyright AFP Image caption More than 100,000 demonstrators marched in Hong Kong in 2017 to call for Joshua Wong’s release
Mr Newman said the fact the release of Mr Ho and other activists had not led to more arrests appeared to be “a politically motivated retaliation against outspoken opposition figures in Hong Kong and Taiwan”.
“The Hong Kong and Taiwan movements are pushing back against growing Beijing interference in their domestic affairs.”
In Hong Kong, at least three petitions have been calling for the release of Mr Ho, who is believed to be in custody.
Human rights group Amnesty International called for Mr Ho’s immediate release, saying the activist was likely being used as a political bargaining chip by Beijing.
“The exiled group CCDI, China’s state security agency, appears to be using him to make a point about the harsh treatment of political activists in Hong Kong,” Amnesty spokesman Albert Ho said.
“In doing so, they are apparently hoping to frighten other dissenting voices off Hong Kong.”