Tens of thousands of protesters have marched on the streets of Hong Kong, calling for the resignation of the chief executive and demanding greater democracy.
Rally organisers said they expected 50,000 people to join the New Year's Day march against Leung Chun-ying, while pro-government groups staged separate and smaller rallies in support of the Beijing-backed leader.
Since taking office in July, Mr Leung's popularity ratings have tumbled and he has faced a no-confidence vote in the legislature amid a row over illegal structures at his luxury home.
The embattled leader has acknowledged and apologised for the structures, which were built without planning permission.
Mr Leung became chief executive after his rival for the post, Henry Tang, was brought down by a row over illegal structures at his own home.
Demonstrators have used the scandal to press for universal suffrage in choosing the leader of Hong Kong.
Earlier, Mr Leung's supporters gathered at a separate rally. Organisers claimed a turnout of 60,000 while police put the figure at around 8,000.
China analyst Willy Lam from the Chinese University of Hong Kong, has told Radio Australia's Asia Pacific the administration is considered the "stooge of Beijing."
"At this stage the Leung government is seen as being too servile to Beijing."
Mr Lam says the anti-government rally on Tuesday attracted several tens of thousands of protesters.
"This is a strong voice for change in Hong Kong, and a strong voice to put pressure on Beijing to quicken the pace of democracy in Hong Kong," he said.
In a bid to tackle discontent, Mr Leung has banned mainland Chinese women from giving birth in Hong Kong in an attempt to secure residence rights for their children.
He has also introduced policies to prioritise housing for locals, a move which analysts say was a reaction to mainland buyers pushing up prices in one of the world's most expensive property markets.
Hong Kong was returned to Beijing in 1997 but maintains a semi-autonomous status, with guarantees of civil liberties such the right to protest not seen on the mainland.
Beijing has said the city's chief executive could be directly elected in 2017 at the earliest, with the legislature following by 2020.
About 1,000 police reportedly deployed for Tuesday's marches, following scuffles over the weekend at a pro-government rally that saw two journalists assaulted.