Chinese President Xi Jinping on Sunday said the PLA has the ability to defeat all invading armies as the world's largest military paraded at an expansive training base in Inner Mongolia to mark its 90th anniversary.

Xi, who commands the strong military force of 2.3 million as chief of the Central Military Commission, said the world was not at peace. The Chinese Army must work to restore peace.

"I firmly believe that our gallant military has both confidence and ability to defeat all invading enemies," said Xi.

The 90th anniversary of the People's Liberation Army (PLA) coincides with the stand-off between Indian and Chinese soldiers at Doklam in Sikkim section of their border.

"Our military has the confidence and ability to write a new chapter in building a strong military and make new contributions towards realization of the China dream of great rejuvenation of the Chinese nation and safeguarding world peace," said Xi in an address aired by the state media. The President was clad in military fatigues.

Inspecting the troops from an open-top jeep at the China's largest military base Zhurihe, Xi said the Communist Party of China and the Chinese people all take pride in the PLA.

Formations of conventional missiles, nuclear missiles and missiles for both nuclear and conventional strikes were displayed to show the country's capacity to deter, fight, restrain and win battles.

"Officers and soldiers, you must unswervingly stick to the fundamental principle and system of the Party's absolute leadership over the Army, always listen to and follow the Party's orders, and march to wherever the Party points to," said Xi in a televised address.

After the Communist Party, the PLA is the second most powerful institution in China.

"The world is not all at peace, and peace must be safeguarded," said Xi.

In 2015, Xi, who favours a lean Army, announced a reduction of 300,000 troops in the PLA. This month, an online news portal run by the PLA said the present force of 2.3 million will be whittled down to below 1 million.

The PLA was founded on August 1, 1927 by the Communists against the Kuomintang regime. The Communists eventually won the civil war, leading to the birth of the People's Republic of China on October 1, 1949.