A delegation is visiting a prison this morning to check the rights of Chinese men facing deportation have been upheld.
Last week, Immigration detained 10 men who officials said were working illegally at construction sites in Auckland.
Nine remain in prison pending deportation arrangements with China.
Their lawyer, Matt Robson, claims the men have been the victims of human trafficking after paying substantial amounts to a third party who arranged travel and work.
Robson said the government had failed in its promise to better protect migrant workrs.
"I am deeply because the minister of immigration is not reading the Cabinet manual and seeing that there's a public policy which they've put out on migrant exploitation... and there are employers in Auckland at the moment, who will be laughing that Immigration New Zealand is doing their job of getting rid of their witnesses against them."
Robson, Green MP Ricardo Menéndez March, and Unite Union representatives visited the men to check on their welfare.
Menéndez March said he wanted assurances about the men's welfare.
"We have concerns that these workers have acknowledged and have signalled that exploitation may have occurred at some point in their journey into New Zealand and while they were in New Zealand.
"We just want to make sure that they get access and they are able to stay here so that a thorough investigation is able to be carried before a decision on deportation is made."
Immigration said the men were working illegally at construction sites in Auckland.
Unite Union, in a statement, said that the workers were not questioned about any claims of exploitation by employers here or claims of human trafficking.
"We discovered they had no chance to get legal representation."
Corrections and Immigration have been approached for comment.