The lawyer acting for a group of Chinese nationals allegedly working illegally at an Auckland building site is calling for an investigation into their situation.
Their lawyer, Matt Robson, alleges they have been victim to human trafficking.
Nine of the men are still in Mount Eden jail awaiting deporation following the bust last week, while another has been separated from the group.
Immigration NZ said none of the men had work visas and some had overstayed by more than three years.
Robson told Checkpoint the men fit under the government's criteria for migrant exploitation.
Being in prison was the wrong place for them and a breach of the government's policy, he said.
He had written to the responsible ministers regarding the case - the minister and associate minister of immigration and the minster of foreign affairs.
"There's a whole lot of questions to ask," he said.
In his opinion, the workers had been trafficked, he said.
"They are because if they paid money and they paid it to agents to bring them for the purpose of working here - they don't speak English, they don't know the law, they just put their ... fate in the hands of these people."
None of the workers had advised Robson they had employment contracts, nor did they have records of wages or time worked, he said.
He said he had been told workers were being exploited widely and it required an investigation by the state.
Asked if he believed there were human traffickers in New Zealand, he said: "Yes".
Checkpoint contacted Immigration NZ but it chose not to comment as the investigation was still ongoing.