Two-thirds of Hong Kong people think China's reported favourite to become the city's next leader should quit the race, a poll showed 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 English daily the South China Morning Post when respondents were asked to pick between him and main rival Leung Chun-ying.

Leung is well ahead of Tang with the backing of 63.9 percent of respondents.

Nearly 66 percent of those questioned also said Tang -- the former number two in the city's government -- should quit the race, following the discovery of an illegal underground leisure space in a house belonging to his wife.

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

The opinion poll was the latest setback for Tang, after another survey published on Sunday found that 51.3 percent of the 516 people asked thought Tang should abandon his campaign.

Last week the wealthy Tang, who many believe is Beijing's preferred candidate to become Hong Kong's next chief executive, was forced to admit that he knew about an unauthorised structure in his wife's home, but blamed her for the idea.

He has defied calls to withdraw his candidacy, and officially nominated himself for the post on Monday. Tang's campaign got off to a shaky start after he publicly admitted cheating on Lisa Kuo, his wife of 27 years.

The March 25 election, which is expected to be heavily influenced by Beijing, will be in the form of a vote by a 1,200-member electoral committee packed with Beijing-backed delegates and members of the business elite.

Analysts say Beijing has been put in a difficult bind of apparently backing a candidate who would appear to have no hope of winning a genuinely democratic election in the semi-autonomous southern city of seven million people.

Candidates have until February 29 to formally nominate, leaving Beijing little time to send another proxy into the contest, they say.

Current Chief Executive Donald Tsang's term ends in June and he is unable to run again. The former British colony was returned to Chinese rule in 1997 and maintains a semi-autonomous status with its own political and legal system.