The president has no say over the appointment of other members of the State Council or the party's all-powerful Politburo Standing Committee. The proposal also covers the vice president position.
"Once people know he will serve for who knows how long, it will strengthen his power and motivate everybody to bandwagon with him", said Zhang.
Experts predicted last October that Xi may seek to stay on as leader after he failed to unveil an obvious successor at a major party congress, appearing to break with an unwritten rule of two five-year terms as head of the party.
Xi's two predecessors, Jiang Zemin and Hu Jintao, both served two five-year terms, but Xi has signalled bigger ambitions. "Getting rid of it is not good!", wrote one Weibo user.
A seven-man leadership committee unveiled previous year included no potential successor, raising the prospect that Xi intends to govern beyond his second term.
Beginning as a county-level party secretary in 1969, Xi climbed to the governorship of coastal Fujian province in 1999, then party chief of Zhejiang province in 2002 and eventually Shanghai in 2007.
Political analysts said the absence of an apparent successor pointed to Xi's longer-term ambitions.
Chinese President Xi Jinping speaks during a joint press briefing at the Great Hall of the People in Beijing, China on January 9, 2018. In Chinese politics, the role of president is largely ceremonial, with real power resting in the hands of the general secretary and the chairman of the Central Military Commission. It has not been used since.
China should make full use of the Constitution's important function in modernizing China's system and capacity for governance and strengthening the Party's long-term governance capacity, said Xi.
"He has got them, though many in the establishment might have offered them somewhat grudgingly", said Mr Tsang.
This development is on expected lines, Professor Alka Acharya of JNU said explaining that the move would be passed down to the lowest level of Communist Party units in China so that the party and the state structure is prepared to carry out this change. "In China, ordinary people already consider Xi Jinping to be the emperor".
Chinese flag is seen in front of the financial district of Pudong amid heavy smog in Shanghai, China, December 23, 2015. In other words, the world of Mao Zedong must never threaten the path of modern China, nor must people become downtrodden based on the political whims of an all-encompassing ruler who dictates to the masses. If Xi were to stay on as China's leader beyond 2022, he would have to defy that tradition. Distinct from the standard usage of "lingdao" for leader, "lingxiu" evokes grander, nearly spiritual, connotations.
"This is a very clear sign that the president will remain in office beyond the existing term limit", Deng said. The party has been laying the groundwork for Xi not to have to go.
When Xi did assume the top spot in 2012, it was as head of a reduced seven-member committee on which he had only one reliable ally, veteran Wang Qishan.
Aged 69, Wang had reached the age at which top officials tend to retire.