Five members of Hong Kong's Legislative Council resigned their seats on Tuesday in a bid to pressure Beijing for full democracy.
The group says the resulting by-election will serve as a referendum on universal suffrage in the territory.
Before Britain handed the colony back to China in 1997, there was a promise of progress towards universal suffrage.
The BBC reports the group wants full direct elections by 2012 - several years ahead of the timetable set by China's government.
Currently, only half of Hong Kong's legislators are directly elected; the rest are chosen by special interest groups, most of whom are pro-Beijing.
Analysts say the resignation plan highlights the deep divide in Hong Kong politics.
Under British rule for more than 150 years, the territory was returned to China in 1997 under a special agreement that promised to retain Western-style practices.
The BBC reports recent opinion polls show public support for actions by pro-democracy groups, is tepid.