A Hong Kong pro-democracy activist said Tuesday he had been fired by his university after he served jail time for taking part in protests, a move that was hailed by China's office in the city.

Law professor Benny Tai, 56, decried his sacking by the University of Hong Kong and accused education chiefs of bowing to political pressure from Beijing.

"It marks the end of academic freedom in Hong Kong," he wrote on Facebook.

"Academic staff in education institutions in Hong Kong are no longer free to make controversial statements to the general public about politically or socially controversial matters," he added.

The Liaison Office, which represents Beijing's government in the semi-autonomous city, released a statement calling Tai "evil" and welcoming the firing.

"The University of Hong Kong's decision to fire Benny Tai is a move that punishes evil and praises the virtuous," the statement said.

Tai is a leading figure within Hong Kong's pro-democracy movement.

A staunch non-violence advocate, he was jailed last year over his involvement in huge pro-democracy protests in 2014 that brought parts of the city to a standstill for weeks.

He is often the target of vitriolic statements from China's government.

State media has previously described him as a "hardcore troublemaker" colluding with foreign forces.

Earlier this month the Liaison Office accused him of trying to launch a revolution because he helped organise primaries to choose pro-democracy candidates to stand in upcoming legislative elections.

Law professor Benny Tai (C) has decried his sacking by the University of Hong Kong
Law professor Benny Tai (C) has decried his sacking by the University of Hong Kong AFP / ISAAC LAWRENCE

The University of Hong Kong did not respond to media enquiries over the sacking.

University chiefs had launched a disciplinary investigation after Tai was released from a 16-month jail sentence last year.

Local media said 18 members of the committee voted for his removal, with two against.

"I am heart-broken to witness the demise of my beloved university," Tai wrote.

"Yet, I will continue my research and teaching on the rule of law in another capacity. My fight for Hong Kong's rule of law also will not stop," he added.

Hong Kong has some of Asia's best universities, aided by free-speech protections denied on the authoritarian mainland.

But Beijing has made no secret of its desire to overhaul schools and universities which it believes are partly responsible for the huge and often violent democracy protests that broke out last year.

China has called for more patriotic education and has imposed a sweeping national security law on Hong Kong which criminalises certain political views, such as calls for independence or greater autonomy.

Schools and libraries have already withdrawn books deemed to breach the new law.

Tai is not the only academic to face repercussions for taking part in protests.

On Monday local media reported that Shiu Ka-chun, another 2014 protest leader who was jailed, was told his contract with Hong Kong Baptist University would not be renewed.