The union for railway workers says Chinese engineers sent to this country to remove asbestos from new locomotives were so broke and hungry that union members took them home and fed them.
Labour's Trevor Mallard has alleged the engineers were paid as little as $3 an hour, during a nine-month stint at the Hutt rail workshops.
The Rail and Maritime Transport Union is taking KiwiRail to court to test a finding that the Chinese workers were probably not covered under New Zealand Employment Law.
The Union's General Secretary, Wayne Butson, said the Ministry of Business, Innovation and Employment could not confirm that figure, because the Chinese refused to produce any wage records.
He said New Zealand rail workers took pity on their Chinese counterparts because they could not afford to eat and, in the end, KiwiRail had to provide lunch to make them fit to work.
Mr Butson said a new batch of Chinese engineers arrived in the country last month. If they were not covered by New Zealand employment law, as the ministry believed, he said, an extremely dangerous precedent would have been set.
He said the union had applied to clarify their rights in the Employment Court and hoped to have a hearing date by next week.