A Vietnamese court sentenced four men to up four years in prison for arranging two illegal sea voyages to Australia for more than 60 would-be migrants, a judge said Wednesday.

The men were found guilty of arranging for 33 people to leave by boat in May 2012. The boat ran aground in Indonesia. The court found the gang arranged another voyage that month but the 28 people were arrested before the journey, Judge Ta Quoc Viet said.

The men received sentences of between 1 ½ and four years at the hearing Tuesday in southern Ba Ria Vung Tau province, said the judge. It was not possible to contact lawyers for the men.

Each passenger was charged between $6,000 and $13,000 for the voyage, most of it to be paid on arrival in Australia, according to Viet.

Australia is a popular destination for economic migrants and asylum seekers, especially those from unstable South Asian and Middle Eastern nations. Thousands take to the seas each year.

Close to 1 million Vietnamese fled after the Vietnam War, many of them boat, but that number had slowed to a trickle until recently. This year more than 460 Vietnamese have arrived in Australian waters, more than in the last five years combined, according to Australian government figures.

The Canberra government, under domestic pressure to stop migrant arrivals, maintains the vast majority are economic migrants and hence have no right to stay in Australia. Some lawyers and advocates say many Vietnamese might be eligible for asylum status given Vietnam's repressive government.