The Rail and Maritime Transport Union says it is disappointed at a decision to not go ahead with an inquiry into a deal between KiwiRail and a Chinese firm.
Labour MP, Clare Curran, put in a request last year to look at the purchase of freight wagons from China Northern Locomotive and Rolling Stock Industry Corporation.
Auditor-General, Lyn Provost, will not inquire because her office says KiwiRail made the decision for normal business and commercial reasons.
The union's general secretary Wayne Butson says an inquiry would have been helpful.
He says an aspect that needs to be assessed is whether KiwiRail considered its obligations as a state owned enterprise operating for New Zealand's best interests.
Mr Butson says the Government has shown no interest in using KiwiRail to support jobs.