President Xi Jinping delivered a blistering nationalist speech today, warning against any attempts to split China and touting the country's readiness to fight "the bloody battle" to regain its rightful place in the world.

Xi's address capped an annual session of the National People's Congress that paved the way for him to rule for life, as China's most powerful leader since Mao Zedong pushes through his vision of guiding the country through a "new era" of unrivalled global military and economic supremacy.

Days after President Donald Trump signed new rules allowing top-level US officials to travel to Taiwan, Xi warned that Beijing would defend its "one China principle", which sees the self-ruling island as its territory awaiting reunification.

"All acts and tricks to separate the country are doomed to fail and will be condemned by the people and punished by history," Xi said.

But he also sought to address concerns about ambitious Chinese development projects abroad, saying they "will not pose a threat to any country."

"Only those who are accustomed to threatening others will see everyone as a threat," he added.

Xi used the speech to espouse his vision of realising the "rejuvenation of the Chinese nation" -- the "greatest dream" of the world's second-largest economy.

"The Chinese people have been indomitable and persistent, we have the spirit of fighting the bloody battle against our enemies to the bitter end," he said.

But his speech was also a reminder that the Communist Party, more than ever, reigns over the country's affairs.

"History has already proven and will continue to prove that only socialism can save China," he said.

"The Communist Party is the supreme political leadership of the country and the fundamental guarantee to achieve the great rejuvenation of the Chinese nation."

Indefinite rule

The two-week session of the National People's Congress handed Xi, 64, a second term and endorsed the Communist Party's decision to lift presidential term limits, clearing the way for him to remain in power indefinitely after his second term ends in 2023.

His eponymous political philosophy, which was enshrined in the party charter last year, was added to the national constitution and senior government officials had to swear an oath to the document for the first time.

Some of Xi's key lieutenants were also promoted to top positions. His former anti-corruption czar, Wang Qishan, was elevated to the vice presidency while his top economic adviser, Liu He, became vice premier.

Wang could use his experience as a trade negotiator to deal with rocky relations with the Trump administration, while Liu is expected to have an influential role in economic policymaking.

The legislature also approved the biggest government shake-up in years, merging the banking and insurance regulators to tackle financial risks, and amended the constitution to expand the Communist Party's role in the country's affairs.

Xi's campaign against corruption within the Communist Party, which punished 1.5 million officials in five years, was expanded as the legislature voted Tuesday to create a national agency that will scrutinise millions of public servants.

"The Communist Party of China must... resolutely eliminate" corruption, Xi said.

The government's propaganda machine worked in overdrive to nurture a cult of personality around Xi and stamp out dissenting views during the two-week session.

The People's Daily, the Communist Party's mouthpiece, referred to Xi as the "helmsman" last weekend, an echo of Mao who was known as "the great helmsman".

The abolition of term limits triggered a rare bout of criticism on social media, prompting censors to block dozens of phrases such as "I disagree" or "emperor" as well as satirical images such as Winnie the Pooh -- the cartoon bear that some compare to Xi.

China has stepped up its crackdown on civil society since Xi took power in 2012, tightening online restrictions and detaining hundreds of activists and lawyers.