Up to 20 protesters tried to force their way into the Convention and Exhibition Centre, Wan Chai, during voting in yesterday's by-elections.
Members of The Frontier and the Social Democratic Forum condemned the 'small circle' poll and called for a directly elected chief executive.
Holding banners and chanting slogans, the protesters marched from the nearby Hong Kong Arts Centre to the polling station. Minor scuffles broke out between some protesters and the venue's security guards when the demonstrators tried to enter the building.
After negotiations, the protesters agreed to withdraw to the entrance of the centre.
Legislator Emily Lau Wai-hing, of The Frontier, said: 'Tung Chee-hwa will definitely serve a second term because no one will run against him. No one will ever need to cast a vote. The whole thing is meaningless.'
After tearing up a paper chain made in the shape of a circle to signify the breaking of the 'small circle' election, the protesters left peacefully.