Wu and seven other pro-democracy activists were granted bail last month after they were charged with inciting people to join unauthorised protests on July 1 last year.
They were ordered not to leave Hong Kong and to surrender all their travel documents.
But Wu has now been accused of keeping a valid BN(O) passport at home, despite the court order.
A hearing at West Kowloon Court was adjourned until Friday, and Wu was remanded in custody for the night.
The former lawmaker was also among the more than 50 pro-democracy figures arrested under the national security law on Wednesday. There have been no reports, however, of any of them being charged with an offence.
HI! I AM DAVID BRAYZ!
I am a highly-skilled IT Specialist with over 12 years of experience in Web Design, Graphic Design, Web Blogging & ITL Management.
Send your news and stories to us firstname.lastname@example.org or email@example.com and WhatsApp: +447747873668.
Before you go...
Democratic norms are being stress-tested all over the world, and the past few years have thrown up all kinds of questions we didn't know needed clarifying – how long is too long for a parliamentary prorogation? How far should politicians be allowed to intervene in court cases? To monitor these issues as closely as we have in the past we need your support, so please consider donating to The Climax News Room.