They also own prime real estate in London, including the Raffles Hotel at the Old War Office in Whitehall, where a top suite costs £25,000 a night.
Since the death of patriarch SP Hinduja last year, the empire has been led by his brother Gopi. Prakash is their younger brother.
The family has been resident in Switzerland since the late 1980s and Prakash obtained citizenship in 2000.
He was previously convicted on similar, but less serious, charges in 2007. However, prosecutors said he continued to employ workers without the proper paperwork.
The Hinduja family reached an undisclosed settlement with staff members last week, concluding a civil case that was first filed six years ago.
An unrelated tax case is still pending against Prakash in Switzerland after the country’s highest court ruled he could owe Genevan authorities more than 125m Swiss francs in back taxes.
The Hinduja family’s legal counsel said in a statement: “Our clients the Hinduja family has been acquitted of all human trafficking charges.
“We are appalled and disappointed by the rest of the decision made in this court of first instance, and we have of course filed an appeal to the higher court thereby making this part of the judgement not effective. Under Swiss law, the presumption of innocence is paramount till a final judgement by the highest adjudicating authority is enforced.
“Contrary to some media reports, there is no effective detention for any members of the family.
“It should also be recalled that the plaintiffs in this case had withdrawn their respective complaints after declaring to the court that they had never intended to be involved in such proceedings.
“The family has full faith in the judicial process and remains confident that the truth will prevail.”