On Monday, The Guardian revealed that the workers left Murrawee Farms because of a contract dispute with employment agency Connect Group. The workers claimed their pay had been unfairly changed from an hourly rate to a performance-based system.

The workers have now returned to Vanuatu and the Fair Work Ombudsman is launching an investigation into Connect Group to determine if any pay or working conditions had been breached.

Ms Tripodi said she was still a supporter of the government's Pacific Seasonal Worker Pilot Scheme -- a joint program between the Federal and Pacific governments to import foreign labour for short-staffed Australian farms.

But she urged the government to review the program so "the right mix of people" were recruited to enhance the horticultural industry and help it cover rising costs.

Ms Tripodi said the Ni-Vans' contracts had been changed in December to a performance-based pay structure -- or piece rates -- because of low productivity. She also said some of the workers had breached their own contracts with the Vanuatu government, but could not comment further while the ombudsman's investigation was in progress.

Ms Tripodi said the workers were receiving an hourly rate of about $19.50, but with piece rates "average, competant workers" had the potential to make about $35 an hour during busy periods.

"It gives the opportunity for workers to make more money. The payoff for the employer is they get more productivity," she said.

"The (Ni-Van) workers missed the opportunity to make very good money, because we were coming to the flush of our crop now."

In an interview with The Guardian last week, employment agency Connect Group also welcomed the ombudsman's investigation.

"Our government has put in incredible safeguards to ensure the mistakes that have been made in other countries with imported labour schemes are not repeated here," Connect Group managing director Michael Fryszer said.

With the 32 workers now back in Vanuatu, they could not be reached for comment.