China's Congress has passed a constitutional amendment that removes presidential term limits, allowing President Xi Jinping to remain in office indefinitely and confirming his status as the country's most powerful leader since Mao Zedong died more than 40 years ago.

The vote passed with two "no" votes and three abstentions among almost 3,000 delegates.

China's ruling Communist Party proposed the amendment last month and there was never any doubt it would pass as Parliament is packed with loyal party members who would not have opposed the proposal.

The amendments also include inserting Mr Xi's political theory into the constitution, a feat no other leader since Mao had managed while in office.

Additionally, clauses were included to give a legal framework to a new super anti-corruption department.

Sorry, this video has expired Inside the Great Hall as Chinese politicians vote to abolish presidential term limits

Reporters were briefly ushered from the main hall as delegates filled in their ballot papers, but allowed in to see them placing the papers, one by one, into large red ballot boxes around the room.

Mr Xi cast his vote first, on the podium at the front of the hall, followed in turn by the other six members of the party's elite Standing Committee, which runs China.

The room erupted into loud applause when the result of the vote was passed, though Mr Xi did not address parliament.

Mr Xi's tenure was due to expire in 2022.

The slide toward one-man rule under Mr Xi has fuelled concern that Beijing is eroding efforts to guard against the excesses of autocratic leadership and make economic regulation more stable and predictable.

Party loyalists say the decision is popular with ordinary Chinese people. ( Chinatopix/AP )

In the run-up to Sunday's vote, critics on social media attacked the move and drew parallels to North Korea or suggested a Mao Zedong-type cult of personality was forming.

But the Government quickly mounted a propaganda push, blocking some articles and publishing pieces praising the party.

Renowned writer Ma, who writes under the pen name Old Ghost, said history was regressing badly.

"There's a lot of fear," said Ma.

"People know that Xi's about to become the Emperor, so they don't dare cross his path. Most people are just watching, observing."

Party loyalists who attended the annual session of congress said the decision was popular with ordinary Chinese people and asserted that China was lucky to have a leader of Mr Xi's calibre.

President Xi Jinping applauds after Congress passes a constitutional amendment lifting the presidential term limit. ( Reuters: Jason Lee )

Mr Xi began his second five-year term as party chief in October and his tenure was due to expire in 2020.

The limit of two five-year presidential terms was written into China's constitution after Mao's death in 1976 by Deng Xiaoping, who recognised the dangers of one-man rule and the cult of personality and instead espoused collective leadership.

The Government said lifting the term limits was about protecting the authority of the party with Mr Xi at its centre.

The party's official newspaper People's Daily said the amendment did not mean lifelong terms.

Sorry, this video has expired Richard McGregor from the Lowy Institute explains Xi Jinping's rise to power

The party gave Mr Xi the title of "core" leader in 2016, a significant strengthening of his position at the time.

While the presidency is important, Mr Xi's positions as head of the party and head of the military are considered more important, and these titles are always given first by state media.

With the passage of the amendment, now none of the posts have formal term limits.

Reuters/AP