WESTMINSTER — It was not so long ago that people who advocated trade with Vietnam faced reprisals and denunciation by staunch anti-communists in this enclave that’s home to the nation’s largest Vietnamese immigrant community.

But with Vietnam’s emerging economy, boosted this week by an invitation to join the World Trade Organization, many Vietnamese are openly discussing business opportunities in their old country.

The shift reflects the growing support among many Vietnamese-Americans for strengthening economic ties with Vietnam, even as some continue to criticize the country’s human rights violations and deep-seated corruption.

“Vietnam has changed. It may not be enough to some people, but there have been dramatic improvements,” said Frank Jao, a prominent developer who launched a major construction project in Vietnam this year.

Jao is based in Little Saigon, a commercial hub in Orange County formed by refugees after the Vietnam War. Some people there have been doing business in Vietnam since the communist nation established diplomatic ties with the United States in 1995.

Many routinely send cash to relatives to help start small businesses in the Asian nation.

Such activities have accelerated in recent years as Vietnam’s economy flourished under a 2001 bilateral economic agreement with the United States. Trade between the former foes has grown from $1.2 billion in 2000 to $7.8 billion last year.

Vietnam, a nation of 84 million people, has Asia’s second-fastest growing economy behind China.

As foreign investments surge in Vietnam, some Vietnamese Americans are raising their stakes in the country they fled decades ago.

Jao made his fortune through $400 million in housing and retail developments in Little Saigon. He assembled $10 million in seed money earlier this year to explore investment projects in Vietnam.

So far Jao and his silent, Vietnamese-American partners have acquired minor shares in a Hanoi-based media company and an Internet and broadcasting company called VietnamNet.

They’re also building a sprawling food processing and distribution complex outside Ho Chi Minh City. The mixed-use facility could provide up to 30,000 jobs and housing for hundreds of workers, Jao said.

“There are more and more Vietnamese-Americans who want to work with us,” Jao said, adding that he expects to receive more funding from venture capital firms.

Jao was just 27 in 1975 when he escaped Vietnam and resettled in Southern California. He started from scratch, selling vacuum cleaners door to door. He said he never thought he would see his homeland again.

Now he travels every few months to Vietnam, where he is seeing more and more manufacturing and construction activities. In the process, the lives of his less-privileged countrymen are improving, he said.

In the past, many investors were discouraged by Vietnam’s inaccessible, cumbersome bureaucracy. But the nation’s expected entry into the WTO has given foreign investors more confidence about working there as market reforms promise to ease business transactions.

For example, Vietnam’s government has approved new enterprise and investment laws that grant equal treatment to foreign and domestic firms.

“The fear has been that you could be shaken down by some official,” said David Dapice, an economics professor at Tufts University who has been studying economic reforms in Vietnam.

“Joining the WTO increases the confidence level for small businesses that Vietnam will play by a more normal set of rules,” he said.

Still, American businesses may not be able to take advantage of the WTO agreement immediately because Congress has yet to grant Vietnam “permanent normal trade relations” status.

President Bush is hoping a bill providing the status will be passed before he visits Hanoi for the Asia-Pacific Economic Cooperation Summit on Nov. 18-19.

But passage has been slowed by concerns that Vietnam has jailed three U.S. citizens of Vietnamese descent who face trial this week on charges of plotting to undermine the Vietnamese government.

The case has heightened the lingering bitterness among some Vietnamese-Americans who remain suspicious of Vietnam’s ruling class.

One critic said communist officials stand to profit from increased foreign investment, with little money trickling down to the laborers and farmers who represent the majority of the work force.

“With the joining of the WTO, the question is, will Vietnam change its policies regarding freedom of speech or freedom to strike. I’m doubtful that it will have any effect,” said Dung Tran, a California representative of the Vietnam Reform Party, an international network of pro-democracy activists.

However, a number of prominent Vietnamese-Americans are advocating free trade with Vietnam as a long-term solution to the country’s political problems.

They include Nguyen Cao Ky, the former vice president of South Vietnam who made headlines in 2004 when, after 29 years in exile, he went back to Vietnam and called for peace and reconciliation.

He urges American-educated Vietnamese to go home and use their technical skills and entrepreneurial experience to help lift the impoverished country.

“Our contributions will help improve Vietnam’s economy, then political change will come,” Ky said.