Immigration officials have seized a group of illegal workers in the north Queensland town of Bowen, some of whom are suspected of acting as labour-hire contractors in the agriculture industry.

Key points: Four men and two women detained from countries including Indonesia, Malaysia, Thailand, South Korea and China

Four men and two women detained from countries including Indonesia, Malaysia, Thailand, South Korea and China At least four acted as labour-hire contractors - intermediaries between the farmer and workers

At least four acted as labour-hire contractors - intermediaries between the farmer and workers Group detained in immigration detention in Brisbane, pending removal from Australia

Border Force officials raided a number of addresses in Bowen last week and detained four men and two women from various countries including Indonesia, Malaysia, Thailand, South Korea and China.

Authorities believe at least four were acting as labour-hire contractors; the intermediaries between the farmer and worker.

It is further alleged they were sourcing illegal labour and sending "sizeable" sums of money offshore.

Commander Robyn Miller said officials were able to trace international money transfers.

"We believe that four of the group were involved in sourcing illegal labour and sending money offshore, which we identified partly through sizeable international financial transactions that had been occurring," Commander Miller said.

The group has been detained in immigration detention in Brisbane, pending their removal from Australia.

The town of Bowen has long been plagued with illegal workers, who are sometimes crammed into small houses and charged exorbitant rent.

Region to be scrutinised by border force

Queensland Compliance acting Inspector Teresa Skellett said the Border Force would conduct future investigations in the region as part of a wider investigation.

"The Australian Border Force has information that there are a number of illegal workers in Australia at the moment," she said.

"It is likely that we will return to that region [Bowen] in the future, just as part of business as usual routine work all around Australia."

She said those detained in this raid was a major achievement for Bowen's agriculture sector.

"It is especially positive [because] we identify labour hire intermediaries who are the middle men in this operation, sourcing that illegal work and taking that money away from Australian contractors," she said.

Bowen Gumlu Growers Association president Carl Walker said it was frustrating there were still people doing the wrong thing in the industry.

He said growers needed to remain vigilant, particularly in terms of labour hire.

"They have got to make sure that the contractors are legit and regularly keep a lookout for what they are doing, what they are paying staff," Mr Walker said.

"In saying that, it is very difficult for a grower who might have hundreds of people working for a contractor."

In December, the ABC reported that various investigations were underway in Bowen after dozens of complaints were raised by members of the community.

People with information about illegal workers or visa over-stayers can call the department's Border Watch Hotline on 1800 009 623 or visit the department's website.