A lotus-shaped float carrying a portrait of revolutionary leader Ho Chi Minh was near the front of the parade in the city renamed after him, AFP journalists saw, and fighter jets and helicopters carry flags flew overhead.

Thousands of people -- many wearing T-shirts emblazoned with the Vietnamese flag -- including families with young children and the elderly stayed out overnight in the streets, sharing food and waiting for the display.

The celebrations come half a century after tanks of communist North Vietnam crashed through the gates of the city's presidential palace, defeating the US-backed South and delivering a painful blow to American moral and military prestige.

"I am proud of having contributed to liberating the south," said 75-year-old veteran Tran Van Truong who had travelled -- dressed in full military uniform -- from the capital Hanoi to see the parade.

"But what's gone is gone, I have no hatred for those from the other side of the battle," Truong told AFP. "We should join hands to celebrate the end of the war."

Around 13,000 people, including veterans, soldiers and members of the public, were to march down Ho Chi Minh City's Le Duan Street, a major thoroughfare which leads to the Independence Palace.

For the first time, more than 300 soldiers from China, Laos and Cambodia took part in the spectacle.

More than 300,000 Chinese troops were involved in the bloody conflict, according to state media, providing crucial anti-aircraft defence support and helping with logistics and supplies.

But this year is the first time Chinese soldiers have ever been part of large-scale commemorations.

Only four years after the end of the Vietnam War, China itself invaded the country, only to be pushed back by Hanoi's troops.

"I think Hanoi is signalling to China that they recognise China's historical contribution," said Zach Abuza, a professor at the National War College in Washington who focuses on Southeast Asian politics.

"It's also another way for them to signal: 'Don't think our foreign policy is lurching towards the Americans.'"

After years of fighting that ended on April 30, 1975, the United States and Vietnam have rebuilt ties to become strong trade partners.

But Hanoi also follows a "bamboo diplomacy" approach, striving to stay on good terms with both Beijing and Washington.

"We owe our success... to huge support from the Soviet Union, China... and solidarity from Laos and Cambodia," top party leader To Lam said in a speech before the parade.

He also credited "progressive people all over the world including American people".

The celebrations come after Chinese President Xi Jinping visited Hanoi this month.

Beijing is trying to position itself as a stable alternative to Washington as Vietnam confronts a threatened 46 percent US tariff and American foreign aid cuts that could jeopardise war legacy programmes.

- Reconciliation, excitement -

After a war that eviscerated much of Vietnam, killing millions of its people as well as 58,000 US servicemen, the North's victory expanded communist rule over the whole country.

Thousands of Vietnamese who worked for the Southern government fled, while others stayed and were forced into re-education camps.

For many years the victory formed the basis of the Communist Party's legitimacy, before its authority became entwined with economic growth and improved living standards.

In an article published Sunday on the government's news portal, To Lam put an unusual emphasis on reconciliation.

He said Vietnamese people must rid themselves of "hatred, separation or division... so that future generations no longer have to experience war".

Most of the population was born after the conflict's end, but many young people appeared excited on Tuesday night as music blared through the streets and huge crowds began to form.

Social media users have been anticipating the parade for days after widespread coverage of rehearsals in the media, which is entirely controlled by the state.

Thang Dang, 19, a physical education student at a university in Ho Chi Minh City, was among 250 of his classmates taking part in the parade, carrying Vietnamese national and Communist Party hammer and sickle flags.

"I will tell my future children about this event," he said ahead of the start. "I am so proud and my family is so proud too."