The funeral procession of former Vietnamese Prime Minister Vo Van Kiet was watched by tens of thousands of mourners Sunday in Ho Chi Minh City. Kiet led the country's economic and diplomatic reforms in the 1990s, and became a sharp critic of government conservatism in his final years. Matt Steinglass reports from Hanoi.

Vietnamese Communist Party chief Nong Duc Manh, left, and President Nguyen Minh Triet, are seen with former Vietnamese PM Kiet's coffin in Ho Chi Minh City, Vietnam, 15 Jun 2008

Vo Van Kiet, Prime Minister of Vietnam from 1991 to 1997, was hugely popular among the foreign diplomats who watched him reestablish diplomatic relations with Western countries and open up the economy to foreign investors.

On Sunday, it became clear Kiet had been hugely popular among his countrymen as well. Tens of thousands of mourners lined the streets of Ho Chi Minh City to watch the procession bearing Kiet's coffin to be cremated.

Kiet died June 11 at a hospital in Singapore at the age of 85. At his funeral, current Prime Minister Nguyen Tan Dung called Kiet "a wholehearted, loyal, irrepressible and heroic Communist," firmly claiming his legacy for Vietnam's Communist Party.

In fact, by the time of his death, Kiet had become a sharp critic of the conservatism of Vietnam's government and Communist Party.

Born in 1922 in Vietnam's southern Mekong Delta, Kiet joined the resistance against the French colonial regime at age 16. By the time the US entered the Vietnam War in the 1960s, Kiet was the head of the Viet Cong shadow government in Saigon. When Hanoi won the war in 1975, Kiet became one of the leaders of the Communist government in the South.

But Kiet argued against Hanoi's attempts to quickly establish an orthodox Communist command economy in the South. By the late 1980s that command economy had failed, and Kiet helped introduce the new policy of "doi moi", welcoming private enterprise and foreign investment.

As the first Southerner to become Prime Minister, Kiet normalized relations with the US and many European countries. He also normalized relations with China, which had been suspended after the border war of 1979. His government laid the foundation of the export-oriented, free-market economy that quadrupled Vietnam's real GDP from 1990 to 2006.

But in his final years, Kiet became dissatisfied with the pace of reform in Vietnam. He wrote editorials arguing that Vietnam should move faster to privatize inefficient state-owned firms.

In a 2007 BBC interview, Kiet criticized the government's arrests of numerous pro-democracy activists. He said Vietnam should be talking to its dissidents, not jailing them.

Such public critique of the Communist monopoly on power is unheard of Vietnam. Few besides Kiet have the moral authority to voice such opinions.

Today, Vietnam faces a period of economic uncertainty, with galloping inflation and a huge trade deficit. Vietnamese blogs have been filled with messages of bereavement.

And for many in today's crowds in Ho Chi Minh City, Kiet's death means the loss of a fellow Southerner whose vision and critical judgment have never been more needed.