Hong Kong's Apple Daily tabloid responded with defiance on Tuesday to the arrest of owner Jimmy Lai under a new national security law imposed by Beijing, promising to fight on in a front-page headline over an image of Lai in handcuffs.

Lai was released on bail in the early hours of Wednesday morning, flanked by his lawyers, and greeted by a throng of supporters who chanted "fight till the end" and "support apple, have an apple a day", referring to the pro-democracy tabloid.

Tuesday's edition of the paper ran with the headline "Apple Daily must fight on" plastered on the front page above an image of Lai in handcuffs.