Apple Daily proprietor Jimmy Lai is on remand until April, after the publisher and pro-democracy campaigner was refused bail on what he says are "trumped up" fraud charges.

While separate charges are being made under Hong Kong's new national security law, the remand charges relate to alleged misuse of Apple Daily Hong Kong's buildings.

Lai, Next Digital chief operating officer Royston Chow Tat-kuen, and chief administrative officer Wong Wai-keung, were charged on Wednesday, but the two executives were released on bail on Thursday.

More than 30 people have now been arrested under the national security law, including three activists jailed on Wednesday over a demonstration outside police headquarters in June last year.

Next Media also publishes a newspaper in Taiwan under the Apple Daily banner.