The man seen as China's preferred choice for the next leader of Hong Kong has seen his popularity fall further in an opinion poll out Saturday, raising questions about Beijing's backing for the candidate.

Henry Tang was favoured by only 26.1 percent of 1,001 respondents in a poll commissioned by the South China Morning Post, the southern city's leading English daily.

His main rival, Leung Chun-ying, is well ahead with the backing of 49.2 percent of respondents, widening the gap between the two to 23.1 percentage points from 19.5 percentage points in a previous poll.

The March 25 election for Hong Kong's chief executive is shaping up to be a close race between Tang, 59, a wealthy businessman and the former number two in the city's government, and Leung, 57, a former cabinet member.

A third candidate, Albert Ho from the pro-democracy camp, garnered only 7.3 percent in the opinion poll.

"Henry Tang's reluctance to face direct debates is definitely one of his weaknesses," the University of Hong Kong's public opinion programme director Robert Chung, who conducted the poll, told the Post.

"Leung's support is about 1.8 times that of Tang. The lead is very significant, at least as of today," Chung added.

Analysts have said that Tang's weak popularity ratings have made it increasingly hard for Beijing to back the 59-year-old, who is also supported by Hong Kong's business elite.

Tang's campaign got off to a shaky start after he publicly admitted cheating on his wife, but analysts say his infidelities are unlikely to stop him becoming the next leader.

The 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.

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.