The Chief District Court Judge has described the actions of four Hawke's Bay men who conspired to help overstayers and ship jumpers live and work in New Zealand as commercial corruption.
Judge Russell Johnson on Friday sent Michael Porter, Miles Elliott and Darminder Singh to jail for three years.
They were formerly directors of Contract Labour Services, which supplied more than 500 workers to orchards and vineyards.
Surjit Singh, who was a pay clerk in the company's Hastings office, will spend nine months on home detention.
Judge Johnson says the men conspired for material benefit. He says the former directors used false subcontractors to hide the use of illegal workers.
Police in Hastings arrested the four in December 2006. Their arrests followed a Department of Labour operation targeting horticultural employers in Hawke's Bay and Marlborough suspected of helping people from overseas to work illegally.