China's plan for President Xi Jinping to remain in office indefinitely has sparked social media opposition, drawing comparisons to North Korea's ruling dynasty and charges of creating a dictator by a Hong Kong pro-democracy activist.

The social media reaction late on Sunday quickly saw China swing into a concerted propaganda push by Monday, blocking some articles and publishing pieces praising the party.

The ruling Communist Party on Sunday proposed to remove a constitutional clause limiting presidential service to just two terms in office, meaning Xi, who also heads the party and the military, might never have to retire.

The proposal, which will be passed by delegates loyal to the party at next month's annual meeting of China's largely rubber stamp parliament, is part of a package of amendments to the country's constitution.

It will also add Xi's political thought to the constitution, already added to the party constitution last year, and set a legal framework for a super anti-corruption superbody, as well as more broadly strengthen the party's tight grip on power.

But it seems the party will have its work cut out trying to convince some in China, where Xi is actually very popular thanks in part to his war on graft, that the move will not end up giving Xi too much power.

"Argh, we're going to become North Korea," wrote one Weibo user, where the Kim dynasty has ruled since the late 1940s. Kim Il Sung founded North Korea in 1948 and his family has ruled it ever since.

"We're following the example of our neighbour,' wrote another user.

The comments were removed late on Sunday evening after Weibo, China's answer to Twitter, began blocking the search term "two term limit".

Widely read state-run newspaper the Global Times, in an editorial carried online late Sunday and published on Monday, said the change did not mean the president will stay in office for ever, though it did not offer much explanation.

"Since reform and opening up, China, led by the Communist Party, has successfully resolved and will continue to effectively resolve the issue of party and national leadership replacement in a law-abiding and orderly manner," it said, referring to landmark economic reforms that begun four decades ago.

The party's official People's Daily reprinted a long article by Xinhua news agency saying most people supported the constitutional amendments, quoting a variety of people proffering support.

"The broad part of officials and the masses say that they hoped this constitutional reform is passed," it wrote.

The WeChat account of the People's Daily, after initially posting a flurry of positive comments under its article, then disabled the comments section completely late on Sunday. It was back again by Monday, complete with remarks lauding the party.

The overseas edition of the same paper's WeChat account removed entirely an article focusing on the term limits, replacing it with the lengthy Xinhua report summing up all the amendment proposals.

In one confusing moment for many Chinese, Xinhua initially only reported the news in English.

The decision has also unsettled some in the Chinese territory of Hong Kong, where authorities have been trying to rein in a pro-democracy movement.

"This move, which would allow for a single individual to amass and accumulate political power, means that China would again have a dictator as her head of state - Xi Jinping," said Joshua Wong, one of the movement's leaders.

"The law may exist in China in form, but this just proves that the Chinese law exists to serve the individual and the party's purposes."

China is likely though to see any such criticism as a plot against the party.

"Every time China deliberates on reforms and key decisions, effect on public opinion is worth pondering," the Global Times wrote. "Misinformation and external forces' meddling will affect public opinion in China."