The court found he instructed eight employees to complete false time sheets - which lead to underpayment over several years - and when detection was likely, tried to cover it up.
The companies and Singh have been ordered to pay more than $300,000 in penalties and $250,000 in reparation.
Regional manager southern, labour inspectorate Jeanie Borsboom said the finding serves as a strong deterrent of this completely unacceptable conduct.
"Employment New Zealand provides free education and resources on employment rights, and works with industries and businesses to lift compliance.
"However, those who deliberately continue to deprive workers of their minimum employment rights, should not be employers."