IN PICTURES: China Flexes Military Muscle For 70 Years Of Communist Party Rule

China is celebrating seven decades of Communist Party rule with a massive display of military power, as President Xi Jinping pledged peaceful development but said the armed forces would defend China's sovereignty.

The event in central Beijing is the country's most important of the year, as China looks to project an image of confidence in the face of mounting challenges.

Chinese President Xi Jinping (C), former presidents Jiang Zemin (center R) and Hu Jintao (center L). Image: Getty.

Xi, dressed in a slate grey "Mao" suit and accompanied by his predecessors Hu Jintao and Jiang Zemin, said China will pursue a mutually beneficial strategy of opening up.

Military troops march past Tiananmen Square. Image: EPA.

In a brief speech marking 70 years of Communist Party rule, Xi also said the country must maintain lasting prosperity and stability in Hong Kong and Macau, and promote the peaceful development of relations with self-ruled Taiwan.

A giant portrait of former Chinese Communist Party leader Mao Zedong passes by Tiananmen Square. Image: Getty

"No force can ever shake the status of China, or stop the Chinese people and nation from marching forward," Xi said from the Gate of Heavenly Peace, where Mao Zedong proclaimed the founding of the People's Republic of China on this day in 1949.

Chinese troops march past Tiananmen Square. Image: EPA

Xi, whose military modernisation program has rattled nerves around the region, then descended to the street and inspected row upon row of military hardware and immaculately presented troops.

Riding past in a black limousine, Xi bellowed; "Hello comrades, hard-working comrades!"

Tanks took part in the parade to celebrate China's military power. Image: AAP

The massed ranks of soldiers shouted back: "Follow the Party! Fight to win! Forge exemplary conduct!"

The parade is the first many of China's advanced weapons have been seen for the first time. Image: AAP

Xi remains broadly popular in China for his aggressive campaign against corruption and for propelling what is now the world's second-biggest economy to the forefront of global politics.

A float celebrating 'Dongfeng', a state-owned automobile manufacturer. Image: AAP

But the Communist Party remains nervous about its grip on power and international standing.

The capital has been locked down for the parade. Police have told residents whose houses look onto the parade route not to look out their windows.

Spectators were treated to a military flyover. Image: Getty

There will be a civilian parade too, of students, model workers, ethnic minorities and even a few foreigners, walking alongside or travelling in floats celebrating China's achievements, officials said last week.

Planes from the Chinese People's Liberation Army (PLA) air force fly in formation. Image: Getty

Once the show is over, 70,000 doves will be released to symbolise peace, according to state media.

In the evening, fireworks will light up Beijing.

People holding a national flag pass by Tiananmen Square. Image: Getty

Xi faces mounting challenges, notably in Hong Kong, where more large-scale protests are expected on Tuesday. Police there have warned of "very serious violent attack".

People take part in the National Day parade in Tiananmen Square. Image: Getty

Hong Kong went into lockdown on Tuesday with barricades in the city centre, shuttered stores and a heavy riot police presence. Embattled Hong Kong leader Carrie Lam is in Beijing for the anniversary celebrations.