Two-thirds of Hong Kong people think China's reported favourite to become the city's next leader should quit the race, a poll suggested Thursday as analysts warned of a "crisis" if he is elected.

Henry Tang was favoured by only 16 percent of the 506 respondents polled in the latest survey commissioned by the South China Morning Post, when respondents were asked to pick between him and main rival Leung Chun-ying.

Leung, who formally presented his nomination papers to the electoral office on Thursday, was well ahead of Tang with 63.9 percent support.

A 1,200-member Electoral Committee will choose Hong Kong's next chief executive on March 25, replacing Donald Tsang whose term is expiring.

A former convener of the Legislative Council, or local parliament, Leung promised to "serve all of Hong Kong's residents" should he be chosen by the pro-Beijing elites who dominate the committee.

"If I am elected, I will be the chief executive of seven million people," he said.

Many Hong Kongers are disenchanted with an electoral system they see as tilted in favour of a small group of China-backed business tycoons who control everything from banks to telecommunications.

A wealthy businessman in his own right, former financial secretary Tang was thought to enjoy Beijing's undeclared backing to become the next leader of the southern banking and trade centre.

But the latest poll showed nearly 66 percent of people think he should quit the race altogether, up from 51.3 percent on Sunday.

Tang's plunging poll ratings come after the discovery last week of an illegal underground entertainment den at his home, and his ham-fisted attempts to blame his wife for building it.

"If Tang finally gets elected against landslide public opinion, there will be a governance crisis," University of Hong Kong pollster Robert Chung told the Post.

"He now embarrasses his nominators," he added, referring to the people on the Electoral Committee who have already pledged their support for his campaign, including the city's richest man, Li Ka-shing.

Candidates have until February 29 to formally enter the race, leaving Beijing little time to send another proxy into the contest.

Hong Kong reverted to Chinese control from British rule in 1997, with a semi-autonomous status that guarantees broad social freedoms under limited democracy.