The rail workers' union are pursuing a claim that Chinese engineers are being exploited in New Zealand.
The union sought their claim be taken straight to the Employment Court for legal reasons, but the Employment Relations Authority (ERA) has ruled it will first deal with the claim.
The Rail and Maritime Transport Union (RMTU) said KiwiRail wasn't complying with good faith and social responsibility, after allowing 40 Chinese workers to carry out work on locomotives brought in from China that were contaminated with asbestos.
The trains were bought from Chinese state-owned CNR Corporation Limited (CNR), and the company sent Chinese workers to remove the asbestos and carry out repairs.
A Labour Inspectorate from Ministry of Business, Innovation and Employment investigated a complaint alleging the Chinese workers were paid $61 per day, well below New Zealand's minimum wage of $14.25 per hour.