RTHK neither confirmed nor denied the claim, saying only that the station conducts regular reviews of its programming content as well as manpower arrangements.
Tsang, who presented the Crazy and Happy radio show every weekday, also used to host RTHK’s controversial satirical show Headliner, before it was axed last year.
He first announced news of his departure on his Facebook page.
“Everyone, I’ve left RTHK. It’s a shame that I never got a proper chance to bid farewell to my listeners,” he wrote, while posting a photo of an emptied locker.
Tsang said he worked for the broadcaster on freelance terms, adding that he was informed by the station after Friday’s show that he “no longer needs to come in next Monday” due to a revamp of the programme.
When asked whether he had expected the sack, Tsang said even though his show was very popular and people had praised his performance, he was “psychologically prepared to leave the position one day” due to the present political climate.
“A lot of changes and decisions made within RTHK have gone against common sense these days”, Tsang added.
He said it was regrettable that he had to leave the station so abruptly as he did not have a chance to say goodbye to people who had tuned in to him for over 20 years.
In response to media enquiries, RTHK said Crazy and Happy is one of the station’s longest-running programmes and has always been extremely popular.
It said as RTHK’s Radio 2 celebrates its 40th anniversary, the broadcaster has decided to revamp the show and bring in “classic elements” by getting the show’s previous presenters to re-join the programme.