There are widespread concerns in the semi-autonomous city that China is tightening its grip, fuelling an independence movement.
In the third consecutive week of chaos in the legislature, pro-independence lawmakers Baggio Leung and Yau Wai-ching entered the chamber despite being banned from doing so, pending the result of a judicial review into whether they can take up their seats.
Yau ran up to a table at the front, set up her own microphone and proceeded to read out her oath of office.
After also trying to take his oath, Baggio was flanked by other pro-democracy lawmakers who pushed and shoved against at least five security officers who surrounded them in a cordon and tried to push them out.
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The meeting was adjourned after security failed to eject Baggio from the chamber.
Pro-Beijing lawmakers shouted: "They are not qualified to take their oaths!" while the democratic camp chanted for them to be allowed to take their pledges.
"My mission today was to complete the oath," Yau told reporters after she was taken out.
Yau and Baggio won seats in citywide polls last month, in which a number of new lawmakers advocating self-determination or independence swept to victory.
But they are yet to be sworn in to the Legislative Council (Legco) - Hong Kong's lawmaking body.
Their oath-taking was put on hold and they have been barred from meetings, pending a judicial review into their first attempt at taking the pledge three weeks ago.
At that ceremony, they draped themselves in "Hong Kong is not China" flags and altered the wording of their pledges, including derogatory terms and expletives.
Local media reported today that China's top legislative body will issue its own interpretation of the city's constitution in a bid to bar the two lawmakers.
Asked whether she was concerned about Beijing stepping in, Yau said: "My concern is the destruction of 'one country two systems'," referring to Hong Kong's semi-autonomous status.
"It means the dictatorship of the CCP government will come to Hong Kong, which no Hong Kong people want to see.