Commercial Radio yesterday sacked outspoken host Li Wei-ling, less than three months after she was moved from her popular morning show.
Civic Party lawmaker Claudia Mo Man-ching called the dismissal "shocking", and Democratic Party chairwoman Emily Lau Wai-hing described it as "an unprecedented attack on the city's press freedom".
The removal of Li, a fierce government critic, comes ahead of the broadcaster's expected bid to renew its licence, which expires in 2016. It also comes a day after the company's chief executive, Stephen Chan Chi-wan, renamed himself chief adviser, saying his former role could be subject to government moves to regulate editorial-like programmes.
Commercial Radio offered no comment on the situation.
A source affiliated with the station said the move showed the management's anger at Li's criticism of the company, adding that the decision was made by several management personnel.
Yesterday had started as a regular workday for Li, and she went to lunch with Democratic Party lawmaker James To Kun-sun.
"Things were perfectly normal," To said. "Li was talking about the guests for Wednesday's and Friday's programmes."
Not long afterwards she got a call telling her she had been fired.
"She was calm; she kind of expected it," said the source.
Li wrote on Facebook last night: "Although they can ruthlessly remove me from my position, they can't stop me from monitoring Hong Kong's current affairs."
The Journalists Association said it was "highly concerned" about her dismissal, calling the radio's lack of an explanation "not responsible". Dozens of journalists and activists held a vigil outside the station last night.
Lawmaker Claudia Mo said she would follow up on the matter at a meeting of Legco's information technology and broadcasting panel.
"Commercial Radio's abrupt and ruthless sacking of Li was shocking. There was not even a notice period for her," said Mo, a former journalist.
Lau demanded a swift explanation from the station.