The aim is to pay lower taxes both in Norway and Poland.NRK has been given access to several contracts which all show very low salaries, even by Polish standards.
One contract showed a wage of NOK 12.00 per hour, while the actual hourly wage was NOK 60.00.
A union spokesman says that often three different contracts are used.
One shows standard wages, and is meant for the unions and the Labour Inspectorate. The other is for the tax authorities in the firm's homeland, and the third is the one the workers is paid by, the spokesman says.