A candidate who confronted Beijing would stand a very slim chance of being elected chief executive in 2017, according to Legislative Council President Jasper Tsang Yok-sing.
And if it did happen, the Beijing-friendly heavyweight said, it would boil down to the fundamental question of the effectiveness of "one country, two systems", not whether the central government should refuse to appoint the elected person.
He was speaking as debate raged on over the arrangements for the 2017 election - with tycoon Henry Cheng Kar-shun describing the Occupy Central movement's plans to shut down the city's business heart in its push for full democracy as "worse than a robbery".
Tsang said Beijing's concern was whether the elected person could be trusted to safeguard the state's interests, for example, when Chinese and American interests conflicted.
"If the voters eventually opt for a candidate whom Beijing has explicitly refused to trust, then it is a problem of Hongkongers' defiance of Beijing instead of how to keep him out of the top job," he said during a meeting with media. "It is about whether the 'one country, two systems' is still working well in Hong Kong."
Separately, Cheng, the New World Development chairman and supporter of Chief Executive Leung Chun-ying, called for Occupy Central to call off its civil-disobedience campaign.
"In a robbery, there will be only one victim," he said. "But the Occupy Central protest will affect the public. It will bring about more serious impacts on the whole of society than a robbery."
Speaking yesterday after the announcement of his group's annual results, he said the campaigners planned to "politically kidnap the public to threaten the central government and fight for [the organisers' version] of universal suffrage".
Tsang's remarks came amid discussion on whether Beijing's right to appoint the chief executive-elect should be substantive or remain a formality.
Some electoral proposals floated by the pro-Beijing camp suggest that the central government should "gate-keep" the top job through the appointment right, while setting a lower nomination threshold so that pan-democratic candidates could run for election.
Tsang said the crux of viable universal suffrage - "accepted by the pan-democrats" - was fairness and openness, but it took time for Beijing to formulate its exact stance.
"To me, no news is good news for now," he said, implying that Beijing was still mulling the issue without taking an extreme position.
"It is a very complex question," he said. "The central government needs some space to think about what actual electoral proposal to support."