Vietnam has sentenced four people smugglers to up to four years in prison for attempting to traffic scores of migrants to Australia by boat, a court official said Wednesday.

The Vietnamese men arranged for 33 people to embark on the dangerous journey to Australia in May 2012, but they failed to reach their destination, judge Ta Quoc Viet told AFP from the southern province of Ba Ria Vung Tau.

"They were stuck in a storm, arrested and then deported back to Vietnam by Indonesian authorities," Viet said.

The men were charging passengers between $6,000 and $8,000, most of it to be paid upon arrival in Australia, he said.

After the unsuccessful attempt, the men started to arrange another voyage for 28 Vietnamese migrants but police uncovered the plan and took them into custody.

Australia is a popular destination for migrants from across Southeast Asia who make perilous journeys in often rickety, overloaded boats to reach its shores.