Hong Kong's elite met behind closed doors Sunday to choose the city's new leader as pro-democracy activists rallied outside, in the hardest fought election since the handover to Chinese rule.
Leaders of the regional financial hub's business, labour and political communities convened the 1,200-member election committee that is responsible for selecting a replacement for outgoing Chief Executive Donald Tsang.
The vast majority of Hong Kong's seven million residents have no right to vote in the "small circle" poll, according to the One Country, Two Systems arrangement by which China has ruled the former British colony since 1997.
Hundreds of pro-democracy activists packed the streets around the harbourside convention centre where the committee meeting is taking place, shouting slogans demanding "direct elections".
Committee members such as Asia's richest man, Li Ka-shing, were mobbed by reporters and harassed by protesters as they arrived to cast their ballots.
Activists and committee members from the Hong Kong Social Workers' General Union shouted slogans such as "Get rid of small-circle", "Give us direct elections" and "Don't vote, don't vote".
Radical lawmaker Leung Kwok-hung arrived in a yellow emperor suit, a pig-wolf mask and holding a paper-mache tank, shouting "I am the king and kingmaker", in a theatrical parody of the election process.
Mainland and Constitutional Affairs Minister Raymond Tam urged the protesters to respect the "rule of law".
"If anyone goes against the election laws, we have sufficient mechanisms to deal with them," he told reporters.
"One country, two systems is the model that we have followed since the return of Hong Kong to China."
Former government adviser Leung Chun-ying, 57, is tipped to win a majority after his campaign was boosted by the last-minute support of the city's biggest pro-Beijing party.
His main rival, former businessman Henry Tang, 59, on Saturday dismissed reports that he was considering bowing out of the race, leaving the establishment camp split between the two leading candidates.
Initially seen as Beijing's preferred choice for the job, Tang disappointed his backers among the city's powerful tycoons with a gaffe-ridden campaign and saw his public approval ratings plunge below 20 percent.
Hong Kong has a semi-autonomous status that guarantees broad social freedoms under limited democracy. China has promised direct elections for the post of chief executive in 2017, but only after it has vetted the candidates.
Polling opened at 9am (0100 GMT) and results are expected around 12.30pm (0430 GMT), officials said.
A second vote will be held later Sunday if the first fails to produce a clear winner. If that fails, a fresh election will be scheduled for May.
Outgoing leader Tsang and his predecessor, Tung Chee-hwa, the city's first post-handover leader, were elected virtually unopposed after receiving the open backing of Beijing.
But the 2012 vote has led to divisions within the semi-autonomous territory's establishment and challenged Beijing's carefully balanced model of governance in partnership with the city's business elite.
The election has been complicated by the behind-the-scenes machinations of mainland China's own once-in-a-decade leadership struggle, with various factions seeking to flex their muscles ahead of the transition later this year.