It is now illegal to be a member of Hong Kong National Party, act on its behalf, or raise funds for it, according to a notice posted by the authorities citing legislation under the Societies Ordinance.
Offenders could face up to three years in prison and fines of up to $12,000, reports CNN.
The decision follows a call by the Hong Kong police in July to outlaw the party under the colonial-era ordinance for posing an "imminent threat to national security".
"The Hong Kong National Party has a very clear agenda to achieve its goal of Hong Kong being made an independent republic. Over the two years it has planned and executed actions to implement the plan," Security Secretary John Lee said on Monday, adding that the party has spread hatred against Chinese immigrants and advocated an "armed revolution" to achieve Hong Kong's independence.
Andy Chan, convenor of the Hong Kong National Party, did not immediately respond to a request for comment. He has always maintained his organization is non-violent.
Last month, Chan gave a hugely scrutinised speech at the Foreign Correspondents Club, which eventually went ahead despite attempts by the government and other figures to pressure the club to drop it, and protests by pro-Beijing groups.
Maya Wang, a Hong Kong-based researcher for Human Rights Watch, said the government's justification for the ban as a pre-emptive step to protect national security, "sets a dangerous precedent, where more non-violent pro-democracy political groups may be similarly banned".
"The ban violates a range of human rights guaranteed to Hong Kong people, including the rights to freedom of association and assembly," she added.
Founded in 2016 to achieve Hong Kong's independence from China, the Hong Kong National Party has already faced restrictions on operating, CNN said.
Chan was one of several separatist candidates barred from standing in 2016's legislative elections and the group has also struggled in the past to get police permission to hold rallies or protests.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
