Nearly 40 years after hundreds of thousands of Vietnamese fled the country's Communist regime by boat, a growing number are taking to the water again.

This year alone, 460 Vietnamese men, women and children have arrived on Australian shores ' more than in the last five years combined. The unexpected spike is drawing fresh scrutiny of Hanoi's deteriorating human rights record, though Vietnam's flagging economy may also explain why migrants have been making the risky journey.

The latest boat carrying Vietnamese cruised into Australia's Christmas Island one morning last month, according to witnesses on the shore. The hull number showed it was a fishing vessel registered in Kien Giang, a southern Vietnamese province more than 2,300 kilometers (1,400 miles) from Christmas Island, which is much closer to Indonesia than it is to the Australian mainland.

Many Vietnamese who have reached Australia have been held incommunicado. The government doesn't release details about their religion and place of origin within Vietnam, both of which might hint at why they are seeking asylum.

Truong Chi Liem, reached via telephone from the Villawood Immigration Detention Center on the outskirts of Sydney, would not reveal details of his case but said, "I'd rather die here than be forced back to Vietnam."

The 23-year-old left Vietnam five years ago but who was detained en route in Indonesia for 18 months. He said Vietnamese simply looking to make more money shouldn't attempt a boat journey, but he also said, "If a person is living a miserable life, faced with repression and threats by the authorities there, then they should leave."

Some Vietnamese reach Australia via Indonesia, following the same route that the far more numerous asylum seekers from South Asia and the Middle East have blazed for more than a decade. Others set sail from Vietnam itself, a far longer and riskier journey.

In separate statements, the Australian and Vietnamese governments said the overwhelming majority or all of the arrivals were economic migrants, which would make them ineligible for asylum. Several Vietnamese community activists in Australia and lawyers who have represented asylum-seekers from the Southeast Asian country dispute that categorization or raised questions over the screening process Australia uses.

Those activists and lawyers also raise concerns about what will become of the migrants, saying that while Australia doesn't want to keep them, Vietnam doesn't want to take them back.

"Vietnam's attitude is that, 'These are people who will never be our friends, so why should we take them back?'" said Trung Doan, former head of the Vietnamese Community in Australia, a diaspora group.

In a statement, the Vietnamese government said it is "willing to cooperate with concerned parties to resolve this issue."

Asylum-seekers are a sensitive issue for Vietnam because their journeys undermine Communist Party propaganda that all is well in the country. They also hark back to the mass exodus after the Vietnam War.

Those Vietnamese who fled persecution by the victorious Communists in the immediate aftermath of the war triggered a global humanitarian crisis. Their plight resonated with the U.S. and its allies, and they were initially given immediate refugee status. In 1989, they had to prove their cases pursuant to the Geneva Convention, and acceptance rates quickly fell as a result. Nearly 900,000 Vietnamese did make it out by boat or over land, with the United States, Canada and Australia accepting most of them.

Vietnam remains a one-party state that arrests and hands long prison sentences to government critics, including bloggers and Roman Catholic activists. Human Rights Watch alleges torture in custody is routine. Christian groups have reported on alleged suspicious deaths in custody.

Most independent human rights activists say that repression has increased over the last two years.

Little is known about the background of those that have made the trip this year.

At least some of those who have arrived in the recent past are Roman Catholics who took part in a protest near a cathedral in the capital, Hanoi, said Kaye Bernard, a refugee advocate who has met some arrivals from Hanoi. Others are said to be involved in land disputes with local authorities.

"I don't think you can generalize but there has been an increase in repression in Vietnam. The sentences are getting longer. There is more fear," said Hoi Trinh, an Australia lawyer of Vietnamese descent who heads an organization helping asylum-seekers. "If more people are more fearful, then more of them will flee."

Peter Hansen, a lawyer and Vietnam expert who advised in some appeals involving recent arrivals from Vietnam, said the small number of cases he was aware of didn't involve intellectuals, bloggers or political dissidents most targeted in the current campaign by the government. But he cautioned that current Australian guidelines on the validity of claims from Vietnam didn't take into account the reality of persecution against certain religious sects in specific parts of the country.

"I can't account for why there has been a significant increase this year, but I can tell you now that I'm absolutely certain that there is a proportion of that number who weren't motivated to come here for economic reasons," he said.

Neighboring countries like Cambodia have continued to receive small numbers of asylum-seekers since the 1990s. Many thousands of Vietnamese have left the country to work in Asia or beyond, either illegally or as exported labor. Many don't return after their contracts end.

Australia appears to be the destination of choice, but the country is already facing a record number of asylum-seekers this year. Under public pressure, the Australian government has made it more difficult for people to be considered for asylum and often detained migrants on isolated islands away from lawyers. Critics say Canberra is avoiding its responsibilities under the U.N. refugee conventions by taking these measures.

Along with other nationalities, the Vietnamese are kept in detention, either on the mainland, on Christmas Island or on the Pacific islands of Nauru and Manus. Families and unaccompanied children are kept in lower-security detention facilities. Four Vietnamese, including a teenager, escaped from one such center in Darwin earlier this week, according to authorities.

Australia's desire to get tough on Vietnamese arrivals appears to have run into a problem: The government in Hanoi has shown no interest in accepting the asylum-seekers, according to activists and lawyers.

Australia can't simply put the migrants on the first plane to Hanoi. They need to have travel documents issued to them by Vietnamese authorities, who must first confirm their identities.

Of the 101 Vietnamese who arrived in Australia in 2011, only six have so far been returned to Vietnam. Very few, if any, have been granted asylum, according to lawyers and activists.

_____

Follow Chris Brummitt on Twitter at twitter.com/cjbrummitt