Wang Zhimin (C), Beijing's envoy to Hong Kong, speaks at the Legislative Council in Hong Kong, April 23, 2018.

Hong Kong and Chinese officials have once more sounded a warning note to anyone wishing to stand for election in the former British colony, with "no guarantees" that anyone calling for democracy in China won't be excluded from public life.

"It is very difficult for the Chief Executive to foresee what will happen in the future and ensure or guarantee anything," Chief Executive Carrie Lam told journalists this week.

"Is it right to talk about one-party dictatorship [in China]? As for the consequences of shouting such slogans, it is also difficult for me to answer here concretely or with assurance," she said.

But she added: "I think it is a reasonable argument that we should also respect the fact that mainland China is a socialist society."

Her comments came after Hong Kong's only delegate to the National People's Congress (NPC) standing committee, Tam Yiu-chung, suggested that people who call for an end to one-party rule in China should be barred from standing for election in Hong Kong.

And on Wednesday, the former head of Beijing's Hong Kong and Macau Affairs Office, Wang Guangya, said calls for an end to one-party rule are illegal and unconstitutional.

He also warned that those calling for an end to one-party rule could be prevented from standing for election to the city's Legislative Council (LegCo).

"They probably shouldn't be allowed, because this view goes against our national constitution, and would be an illegal act," Wang told reporters. "It is laid down in the constitution that China is governed by the Chinese Communist Party."

"As to whether we are a dictatorship, it's pretty clear what such slogans are driving at," he said.

Last month, former student protest leader Agnes Chow, now a member of the fledgling political party Demosisto, was disqualified from running in an election, because her political views were judged to be pro-independence.

The barring of certain candidates because of their political views sparked widespread criticism among barristers, rights groups and politicians, as well as among former British and Hong Kong officials, who said the move was a blow to democracy and freedom of expression in the former British colony.

But an extension of the ban to include calls for a democratic China would make it much harder for pro-democracy politicians and rights activists who have made the demand in the past to stand for election, regardless of their views on independence.

‘Irresponsible’ comments

Calls for an end to "one-party dictatorship" in China are often heard at the annual June 4 vigil to mark the 1989 Tiananmen massacre in Hong Kong.

Democracy campaigner Joseph Cheng, a former political science professor at City University, said Tam's comments were "irresponsible," however.

"Returning officers [who administer elections] aren't part of the judiciary or officials of the justice department," Cheng told RFA.

"These deputies to the NPC have no concept of what the rule of law means," he said.

"They are acting irresponsibly and trying to put invisible pressure on the people of Hong Kong," he said. "There is already enough forbidden speech that can rule you out of standing in elections."

"What they are doing goes against the basic principles of human rights, and as such is unacceptable," Cheng said.

Raymond Chan, a pro-democracy lawmaker for the People Power coalition, said he and other pan-democrats had boycotted a meeting with Beijing's Hong Kong envoy Wang Zhimin on Wednesday, choosing instead to demonstrate outside.

"The last thing we need is to put on a show to maintain an atmosphere of harmony and reconciliation, so we chose to demonstrate outside," Chan said.

"[Beijing] is just doing this for show, and because they are hoping for more support for their legislation in LegCo, not for a genuine dialogue with lawmakers," he said.

Reported by Gao Feng for RFA's Mandarin Service and by Lam Kwok-lap for the Cantonese Service. Translated and edited by Luisetta Mudie.